Non-aqueous Electrolyte Battery Binder Coverage Control
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries exhibit high resistance at room temperature, which hampers their input-output characteristics in applications such as electric vehicles and power tools.
Innovation Solution
Incorporating a phosphate compound in the positive electrode and an amorphous/non-crystalline carbon material in the negative electrode, with a rubber-based binder coverage ratio of 0.5 or less, to reduce the resistance by suppressing the formation of high-resistance coating films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rubber-based binder is used to coat the carbon material surface, then adhesion and structural integrity are improved, but resistance increases due to formation of high-resistance coating films
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by specifying a rubber-based binder with particular properties (polybutadiene, polyacrylonitrile, or carboxymethyl cellulose) and controls the coverage ratio parameter to be 0.01 to 0.5, thereby reducing resistance while maintaining adhesion through optimized material selection and parameter control
Solution Approach 2:
The patent uses composite material structure by combining rubber-based binder with specific carbon materials (amorphous carbon, graphite, or carbon fiber) in controlled ratios, creating a composite electrode material that balances adhesion properties with low resistance characteristics
2Power
If carbon black is added to graphite surface, then load characteristics are improved, but resistance increases at room temperature
Solution Approach 1:
The patent merges carbon black with graphite in a composite structure where carbon black particles are distributed on the graphite surface, combining the high conductivity and load characteristics of carbon black with the structural stability of graphite, while the controlled rubber-based binder coverage ensures low resistance
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 significantly reduces the battery's resistance at room temperature, enhancing its input-output characteristics and improving safety during overcharging.
Implementation Method 1
the use of an electrode containing inorganic particles (e.g., Li3PO4) having an ability to transfer lithium ions suppresses the reaction between the electrode active material and the electrolyte solution
Implementation Method 2
adhesion of carbon black to the surface of graphite, which is used as a conductive agent in the negative electrode
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes a non-aqueous electrolyte and an electrode body in which a positive electrode plate and a negative electrode plate are layered with a separator interposed therebetween. The positive electrode plate contains a phosphate compound. The negative electrode plate contains a graphite-based material, an amorphous/non-crystalline carbon material, and a rubber-based binder. The ratio of the coverage of the rubber-based binder on the amorphous/non-crystalline carbon material to the coverage of the rubber-based binder on the graphite-based material is more than 0 and 0.5 or less.