Positive Electrode Layering With CNT for Output-Conductivity Balance
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Solution Overview
Problem
The existing use of carbon nanotubes (CNT) as conductive auxiliary agents in positive electrode plates for lithium ion secondary batteries improves output characteristics but can lead to excessively high electric conductivity, which is undesirable.
Innovation Solution
A positive electrode plate design that incorporates a core body with an active material layer, where the conductive auxiliary agent near the surface opposite to the core body includes CNT, and acetylene black near the core body side, with a particle packing density of 3.0 to 3.8 g/cm3, to balance conductivity and output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon nanotube (CNT) is used as a conductive auxiliary agent in a positive electrode plate, then output characteristic is improved, but electric conductivity becomes too high
Solution Approach 1:
The patent applies local quality by concentrating CNT in the surficial layer (near the surface opposite to the core body) while using acetylene black in the deep layer (near the core body side). This spatial differentiation of conductive auxiliary agents allows the surficial layer to provide high output characteristics through CNT's excellent conductivity, while the deep layer maintains controlled overall conductivity through acetylene black, resolving the contradiction between improving output and preventing excessive conductivity.
Solution Approach 2:
The patent segments the active material layer into two distinct layers: a deep layer adjacent to the core body and a surficial layer adjacent to the surface opposite the core body. Each layer is assigned different conductive auxiliary agents (acetylene black in deep layer, CNT in surficial layer) with different conductivity characteristics. This segmentation enables independent optimization of each layer's function, allowing the surficial layer to enhance output while the deep layer controls overall conductivity.
2Reliability
If the content of CNT in the positive electrode plate is reduced, then electric conductivity is suppressed from being too high, but output characteristic is less likely to be improved
Solution Approach 1:
Instead of uniformly reducing CNT content throughout the electrode plate, the patent applies local quality by concentrating CNT specifically in the surficial layer while using acetylene black in the deep layer. This allows the surficial layer to maintain high output characteristics through CNT's superior conductivity, while the deep layer's acetylene black content suppresses overall excessive conductivity, thus resolving the contradiction without sacrificing output performance.
Solution Approach 2:
The patent employs composite materials by combining two different conductive auxiliary agents (CNT and acetylene black) with distinct conductivity properties in different layers. CNT in the surficial layer provides high conductivity for excellent output characteristics, while acetylene black in the deep layer provides moderate conductivity to control overall electrode conductivity, creating a composite structure that balances both requirements.
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 enhances output characteristics while preventing electric conductivity from becoming too high, resulting in a battery with improved performance and controlled conductivity.
Implementation Method 1
the conductive auxiliary agent present in a vicinity of a surface of the active material layer opposite to the core body includes a carbon nanotube
Implementation Method 2
a particle packing density of the active material layer is 3.0 to 3.8 g/cm3
Data Source
AI summary
The present disclosure relates to a positive electrode plate including a core body and an active material layer, wherein the active material layer includes a conductive auxiliary agent, and the conductive auxiliary agent present in a vicinity of a surface of the active material layer opposite to the core body includes a carbon nanotube. The present disclosure also relates to a non-aqueous electrolyte secondary battery including the positive electrode plate. According to the present disclosure, there are provided: a positive electrode plate in which an output characteristic is improved and electric conductivity is suppressed from being too high; and a non-aqueous electrolyte secondary battery including the positive electrode plate.