Positive Electrode Binder Layer to Suppress Battery Gas Generation
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Solution Overview
Problem
Existing battery technologies face challenges in suppressing gas generation and improving safety, particularly in the design of positive electrodes and electrolyte systems, which can lead to swelling and thermal instability.
Innovation Solution
Incorporating a fluorine-based binder with a melting point of 166° C. or less in the positive electrode active material layer, along with a fluororesin and particle intermediate layer between the positive electrode and separator, to enhance binding properties and reduce gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional binder is used in the positive electrode, then the electrode structure is simple and easy to manufacture, but gas generation occurs and safety is compromised
Solution Approach 1:
The patent uses a composite binder system comprising both a fluorine-based binder and a carboxymethyl cellulose-based binder in the positive electrode. This composite material approach allows the fluorine-based binder to provide thermal stability and suppress gas generation, while the carboxymethyl cellulose-based binder contributes to electrode structure formation and manufacturing feasibility, thus resolving the contradiction between safety and manufacturing simplicity.
Solution Approach 2:
The patent specifies precise parameter ranges for the fluorine-based binder content (0.5-2.8% by mass) and melting point (166°C or less) to optimize both safety performance and manufacturing characteristics. By carefully controlling these parameters, the invention achieves improved battery safety without excessively complicating the electrode structure or manufacturing process.
2Object-generated harmful factors
If the fluorine-based binder content is increased to suppress gas generation, then safety improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent optimizes the fluorine-based binder content within a specific range (0.5-2.8% by mass) to achieve effective gas suppression while avoiding excessive binder usage that would complicate manufacturing and increase costs. This parameter optimization ensures sufficient safety performance without over-engineering the electrode structure.
Solution Approach 2:
The patent employs a composite binder system where the fluorine-based binder (0.5-2.8% by mass) works synergistically with the carboxymethyl cellulose-based binder. This composite approach distributes the functional requirements between two materials, allowing the fluorine-based component to focus on gas suppression while the carboxymethyl cellulose component handles structure formation, thereby maintaining manufacturing simplicity.
3Temperature
If a fluorine-based binder with low melting point is used to improve safety, then thermal stability is enhanced, but binding strength may be reduced
Solution Approach 1:
The patent combines a fluorine-based binder with low melting point (166°C or less) for thermal stability with a carboxymethyl cellulose-based binder for structural integrity and binding strength. The carboxymethyl cellulose component compensates for the potentially reduced strength of the low-melting-point fluorine-based binder, while the fluorine-based component provides the necessary thermal stability, thus resolving the contradiction between temperature resistance and mechanical strength.
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 battery swelling and improves safety by maintaining thermal stability and preventing positive electrode material detachment during charging and discharging.
Implementation Method 1
a positive electrode active material layer including a fluorine-based binder having a melting point of 166° C. or less
Implementation Method 2
The fluororesin included in the surface layer is configured to hold an electrolytic solution. The fluororesin holding the electrolytic solution may be in a gel state.
Implementation Method 3
a fluorine-based binder having a melting point of 166° C. or less
Data Source
AI summary
A battery includes a positive electrode; a negative electrode; a separator; and an intermediate layer. The intermediate layer is provided between the positive electrode and the separator and includes one or both of a fluororesin and a particle. The positive electrode has a positive electrode active material layer including a fluorine-based binder having a melting point of 166° C. or less, and a content of the fluorine-based binder in the positive electrode active material layer is from 0.5% by mass to 2.8% by mass.