Secondary Battery Paste Composition for Adhesion and Low Resistance
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Solution Overview
Problem
Conventional pastes for secondary batteries lack sufficient adhesiveness of the electrode mixed material layer and exhibit high internal resistance, which hinders the performance of secondary batteries.
Innovation Solution
A paste for secondary batteries containing carbon nanotubes with specific surface properties, a polymer with nitrile and conjugated diene monomer units, and a dispersion medium, which enhances adhesiveness and reduces internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional paste formulations are used, then manufacturing simplicity is maintained, but adhesiveness of electrode mixed material layer is insufficient and internal resistance is high
Solution Approach 1:
The invention changes the chemical parameters of the conductive additive by specifying surface acid content (0.01-0.15 mmol/g) and surface base content (0.005-0.500 mmol/g) of carbon nanotubes, along with their ratio (1.3-3.0). These parameter modifications enable the carbon nanotubes to exhibit enhanced adhesiveness while maintaining formulation simplicity, directly resolving the contradiction between improving reliability and avoiding increased complexity
Solution Approach 2:
The invention uses carbon nanotubes as a composite conductive additive that combines electrical conductivity with adhesive properties. The carbon nanotubes with specific surface characteristics form a composite structure that simultaneously provides both conduction and adhesion functions, eliminating the need for separate adhesive components and maintaining manufacturing simplicity while improving electrode layer adhesiveness
2Reliability
If conventional conductive additives are used, then paste formulation simplicity is maintained, but internal resistance of secondary battery is high
Solution Approach 1:
The invention modifies the physical and chemical parameters of the conductive additive by specifying surface acid content (0.01-0.15 mmol/g), surface base content (0.005-0.500 mmol/g), and specific surface area (150 m²/g or more) of the carbon nanotubes. These parameter changes enable superior electrical conductivity and lower internal resistance while keeping the paste formulation simple and manufacturable
3Reliability
If carbon nanotubes with specific surface properties are used, then adhesiveness and internal resistance are improved, but conductive additive cost increases
Solution Approach 1:
The invention optimizes the surface treatment parameters of carbon nanotubes to achieve the minimum effective surface acid content (0.01 mmol/g) and surface base content (0.005 mmol/g), which reduces treatment complexity and cost while maintaining the required performance. The specific surface area requirement (150 m²/g or more) is set at a practical threshold that balances performance improvement with manufacturing cost
Solution Approach 2:
The invention uses carbon nanotubes as a multi-functional composite material that simultaneously provides conductivity, adhesion, and structural integrity. This composite approach eliminates the need for multiple separate additives, reducing the total quantity of substances required and offsetting the higher unit cost of surface-treated carbon nanotubes through reduced overall material usage
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 paste improves adhesiveness and reduces internal resistance, leading to better performance and cycle characteristics of secondary batteries.
Implementation Method 1
the conductive additive includes one or more carbon nanotubes having a surface acid content of not less than 0.01 mmol/g and not more than 0.15 mmol/g, a surface base content of not less than 0.005 mmol/g and not more than 0.500 mmol/g, and a ratio of the surface acid content relative to the surface base content of not less than 1.3 and not more than 3.0
Implementation Method 2
a specific surface area of 150 m2/g or more... through an electrode that includes this electrode mixed material layer, it is possible to reduce internal resistance of a secondary battery
Data Source
AI summary
Provided is a paste for a secondary battery that can cause an electrode mixed material layer to display excellent adhesiveness and can reduce internal resistance of a secondary battery. The paste for a secondary battery contains a conductive additive, a polymer, and a dispersion medium. The conductive additive includes one or more carbon nanotubes having a surface acid content of not less than 0.01 mmol/g and not more than 0.15 mmol/g, a surface base content of not less than 0.005 mmol/g and not more than 0.500 mmol/g, a ratio of the surface acid content relative to the surface base content of not less than 1.3 and not more than 3.0, and a specific surface area of 150 m2/g or more.