Positive Electrode Sheet Composition for Adhesion and Conductivity
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Solution Overview
Problem
Existing lithium-ion battery technologies face challenges in achieving optimal performance due to issues with the composition and distribution of materials in the positive active layer, leading to reduced energy storage density, conductivity, and cycle capacity retention.
Innovation Solution
The positive electrode sheet incorporates a positive active layer with a specific mass fraction ratio of positive active material, binder, and conductive agent, ranging from 24.5 to 34.5, ensuring balanced conductivity and adhesion, and includes a priming-coat layer to enhance adhesion on the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the mass fraction of positive active material is increased to improve energy storage density, then the energy storage density is improved, but the conductivity and adhesion of the positive active layer deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mass fraction ratio of positive active material to binder and conductive agent within 24.5-34.5. This quantitative parameter optimization ensures sufficient active material for high energy storage density while maintaining adequate binder for adhesion and conductive agent for conductivity, thus resolving the contradiction between quantity and quality
Solution Approach 2:
The patent uses composite materials by formulating a multi-component positive active layer containing positive active material, binder, and conductive agent in specific proportions. This composite structure combines the high capacity of active material with the functional properties of binder (adhesion) and conductive agent (conductivity), achieving balanced performance across multiple parameters
2Reliability
If the mass fraction of binder and conductive agent is increased to improve conductivity and adhesion, then the conductivity and adhesion are improved, but the energy storage density deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the upper limit of the mass fraction ratio to 34.5, ensuring that binder and conductive agent content is sufficient for good conductivity and adhesion while preventing excessive content that would reduce energy storage density. This precise parameter control balances competing requirements
3Ease of manufacture
If the composition ratio of positive active layer is not optimized, then the manufacturing process is simple, but the cycle capacity retention and impedance characteristics deteriorate
Solution Approach 1:
The patent establishes a specific parameter range (24.5-34.5) for the mass fraction ratio that simultaneously achieves good cycle capacity retention and reasonable impedance characteristics. This parameter optimization maintains manufacturing simplicity by using conventional materials and processes while achieving superior performance through precise compositional control
Data Source
AI summary
The present application provides a positive electrode sheet, a battery, an energy storage device, an electrical system and an energy storage system. The present application provides a positive electrode sheet, including: a positive current collector; and a positive active layer. The positive active layer is disposed on a side of the positive current collector. The positive active layer includes a positive active material, a binder and a conductive agent. In the positive active layer, an average mass fraction of the positive active material is x, an average mass fraction of the binder is y, and an average mass fraction of the conductive agent is z. The positive active layer satisfies a relationship: 24.5≤x/(y+z)≤34.5. The positive active layer of the positive electrode sheet of the present application has a good adhesion on the positive current collector and is not easy to lose powder or material.