Negative Electrode Binder System for Secondary Battery Adhesion
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Solution Overview
Problem
Current secondary batteries face challenges in achieving optimal battery characteristics, such as energy density and adhesion between electrodes, which affect their performance and lifespan, particularly in small-size and light-weight applications like electronic devices and electric vehicles.
Innovation Solution
A negative electrode configuration for secondary batteries is developed, comprising particulate active materials with an average size of 5 μm to 30 μm, a styrene butadiene rubber-based binder, and polyvinylidene fluoride-based binders with particle sizes between 0.1 μm and 10 μm, enhancing adhesion and energy storage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two or more aqueous binders are used to improve adhesion between separator and electrode, then adhesion is improved, but device complexity increases
Solution Approach 1:
The patent uses a composite binder system comprising both aqueous binder (carboxymethyl cellulose and/or polyvinyl alcohol) and nonaqueous binder (styrene butadiene rubber and/or polyvinylidene fluoride) in specific weight ratios. This composite approach combines the advantages of both binder types to achieve improved adhesion between the separator and electrode while maintaining manageable complexity through defined composition ranges.
2Reliability
If smaller particle size binders are used to enhance adhesion, then adhesion is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise particle size parameters for the binders: nonaqueous binder with average particle size of 0.1-10 μm and aqueous binder with average particle size of 1-10 μm. By defining these specific parameter ranges, the patent optimizes adhesion strength while establishing clear manufacturing specifications to control particle size, thereby balancing performance improvement with manufacturability.
Data Source
AI summary
The secondary battery includes an electrolytic solution, a positive electrode and a negative electrode, and the negative electrode includes a plurality of particulate negative electrode active materials, a first negative electrode binder, and a plurality of second negative electrode binders with an average particle size smaller than the plurality of particulate negative electrode active materials. The plurality of particulate negative electrode active materials have an average particle size of 5 μm or more and 30 μm or less. The first negative electrode binder includes one or both of a styrene butadiene rubber and a derivative thereof. The plurality of second negative electrode binders include one or both of a polyvinylidene fluoride and a derivative thereof, and the plurality of second negative electrode binders have an average particle size of 0.1 μm or more and 10 μm or less.