Negative Electrode Paste Control for Battery Resistance and Life
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Solution Overview
Problem
Existing methods for manufacturing negative electrode plates in rechargeable batteries, such as those disclosed in Japanese Laid-Open Patent Publication No 2010-272287, rely solely on the blackness of the primary kneaded material to determine battery performance, neglecting other critical factors like viscosity and mixing ratios, which affects battery resistance and duration characteristics.
Innovation Solution
A method involving kneading a negative electrode active material and additive to form a mixture paste with a blackness range of 4 to 16 and a negative electrode thickener viscosity of 13000 mPa s to 21000 mPa s at a shear rate of 0.01 s−1, optimizing the mixture's characteristics to improve battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If only the blackness of the primary kneaded material is used to determine battery performance, then the inspection process is simple, but the battery performance optimization is insufficient
Solution Approach 1:
The patent introduces multiple parameters (blackness, viscosity, shear rate) to comprehensively evaluate the primary kneaded material, moving beyond the single parameter (blackness) approach. By measuring viscosity at specific shear rates and combining multiple parameters, the evaluation becomes more accurate while maintaining procedural simplicity through standardized measurement conditions.
2Stability of the object's composition
If the viscosity of the negative electrode thickener is increased to improve material dispersion, then the dispersion quality improves, but the resistance characteristic deteriorates
Solution Approach 1:
The patent identifies an optimal viscosity range (13000-21000 mPa·s at 0.01 s⁻¹ shear rate) for the negative electrode thickener. By controlling the viscosity within this specific range, the patent achieves a balance between sufficient material dispersion and acceptable resistance characteristics, resolving the trade-off between these two competing requirements.
3Duration of action of moving object
If the blackness of the kneaded material is increased to improve battery duration characteristic, then the duration characteristic improves, but the resistance characteristic may deteriorate
Solution Approach 1:
The patent controls the blackness of the kneaded material within a specific range (4-16) rather than maximizing it. By optimizing blackness within this range and combining it with controlled viscosity parameters, the patent achieves both improved duration characteristic and acceptable resistance, resolving the contradiction between these two performance aspects.
Data Source
AI summary
A method for manufacturing a negative electrode plate of a rechargeable battery is provided. The method includes kneading a negative electrode active material and a negative electrode additive to form a negative electrode mixture paste; applying the negative electrode mixture paste to a negative electrode current collector; and drying the negative electrode mixture paste. The blackness of a material prepared by kneading the negative electrode active material and the negative electrode additive is set in a range of 4 to 16. The viscosity of a negative electrode thickener contained in the negative electrode additive is set in a range of 13000 mPa·s to 21000 mPa·s when a shear rate is 0.01 s−1.