Negative Electrode Slurry Composition for Battery Swelling Inhibition
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Solution Overview
Problem
Conventional slurry compositions for non-aqueous secondary battery negative electrodes do not adequately inhibit swelling, which affects the performance and reliability of secondary batteries.
Innovation Solution
A slurry composition containing graphite particles with a specific orientation ratio, composite particles with conductive carbon films covering silicon oxide particles, and a particulate polymer with an ethylenically unsaturated carboxylic acid monomer unit within a specific range, dispersed in water, is used to form a negative electrode that suppresses electrode swelling and gas release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional slurry composition is used for negative electrode formation, then the electrode can be manufactured with standard materials, but the secondary battery exhibits swelling and increased internal resistance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the orientation ratio of graphite particles (I004/I110 between 7.5-9.5) and the composition ratios of polymer components (polyacrylic acid 5-20 parts, polyvinyl alcohol 50-90 parts per 100 parts graphite). These specific parameter ranges transform the slurry composition to achieve swelling inhibition while maintaining manufacturability.
Solution Approach 2:
The patent uses composite materials by combining graphite particles with specific orientation ratios, polyacrylic acid, polyvinyl alcohol, and water in defined proportions. This composite slurry composition creates a negative electrode that achieves both swelling inhibition and good battery characteristics without excessive complexity.
2Reliability
If graphite particles with high orientation ratio are used, then swelling is inhibited, but manufacturing precision requirements increase
Solution Approach 1:
The patent transforms the manufacturing approach by specifying a range for the orientation ratio (I004/I110 between 7.5-9.5) rather than requiring a single precise value. This parameter range approach maintains electrode structure stability while providing manufacturing flexibility.
Solution Approach 2:
The patent applies preliminary action by pre-processing graphite particles to achieve the desired orientation ratio before slurry formation. This ensures the graphite particles are properly oriented prior to electrode assembly, reducing the need for post-processing adjustments and simplifying manufacturing precision requirements.
3Quantity of substance
If silicon oxide particles are used as negative electrode active material, then capacity is improved, but electrode swelling occurs without proper surface treatment
Solution Approach 1:
The patent applies flexible shells and thin films by coating silicon oxide particles with a polymer matrix consisting of polyacrylic acid and polyvinyl alcohol. This thin film coating allows the high-capacity silicon oxide to expand and contract during charge-discharge cycles without causing electrode swelling, thus maintaining both capacity and reliability.
Solution Approach 2:
The patent uses composite materials by creating a core-shell structure where silicon oxide particles (providing capacity) are combined with polymer materials (providing structural stability). The composite negative electrode mixed material layer integrates the high capacity of silicon oxide with the swelling-inhibition properties of the polymer matrix.
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 effectively inhibits electrode swelling and gas release, enhancing the stability and performance of non-aqueous secondary batteries by maintaining electrode structure integrity and reducing internal resistance.
Implementation Method 1
the orientation ratio is a ratio I 004 /I 110 of integrated intensity I 004 of a peak for (004) planes of the graphite particles and integrated intensity I 110 of a peak for (110) planes of the graphite particles as measured by powder X-ray diffraction
Implementation Method 2
composite particles in which a conductive carbon film at least partially covers the surface of a specific silicon oxide particle
Implementation Method 3
an electrode mixed material layer (negative electrode mixed material layer) formed on the current collector. The negative electrode mixed material layer is, for example, formed using a slurry composition
Data Source
AI summary
Provided is a slurry composition for a non-aqueous secondary battery negative electrode that can form a negative electrode that can inhibit secondary battery swelling. The slurry composition for a non-aqueous secondary battery negative electrode contains a particulate polymer, water, and a negative electrode active material that includes negative electrode active materials (A) and (B). The negative electrode active material (A) is graphite particles having an orientation ratio of not less than 7.5 and not more than 9.5. The negative electrode active material (B) is composite particles each including a silicon oxide particle and a conductive carbon film at least partially covering a surface of the silicon oxide particle. The silicon oxide particle contains silicon oxide represented by SiOx (0.5 ≤ x < 1.6). The particulate polymer includes an ethylenically unsaturated carboxylic acid monomer unit in a proportion of not less than 10 mass% and not more than 70 mass%.