Resin Current Collector Surface Control for Li-Ion Cycle Life
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Solution Overview
Problem
Conventional resin current collectors for lithium ion batteries suffer from inadequate cycle characteristics due to oxidative decomposition currents, which are exacerbated by high surface areas of conductive carbon fillers, leading to reduced battery durability and performance.
Innovation Solution
A resin current collector with a polyolefin resin and conductive carbon filler, where the total surface area of the conductive carbon filler is controlled between 7.0 m² and 10.5 m² per gram, reducing oxidative decomposition currents and improving cycle characteristics by minimizing side reactions and electrolyte solution impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin current collector with high surface area conductive carbon filler is used, then electrical conductivity is improved, but oxidative decomposition current increases and cycle characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the total surface area of conductive carbon filler to 10.5 m²/g or less, and specifically 7.0 m²/g or less. This quantitative parameter control reduces the oxidative decomposition current while maintaining sufficient electrical conductivity, thereby improving cycle characteristics of the lithium ion battery.
Solution Approach 2:
The patent uses composite materials by combining polyolefin resin with conductive carbon filler in a specific composition ratio. The composite structure allows the material to exhibit both the chemical stability of polyolefin and the electrical conductivity of carbon filler, while the controlled surface area minimizes harmful oxidative decomposition.
2Loss of energy
If conductive carbon filler with large total surface area is used, then electrical conductivity increases, but side reactions and decomposition reactions increase
Solution Approach 1:
The patent changes the critical parameter of surface area by limiting it to 10.5 m²/g or less. This parameter optimization reduces the contact area between electrolyte and carbon filler surface, minimizing side reactions and decomposition reactions, thus reducing decomposition current and improving cycle life.
3Weight of moving object
If resin current collector is used instead of metal foil, then weight is reduced and output per unit mass is improved, but cycle characteristics become insufficient
Solution Approach 1:
The patent employs composite materials consisting of polyolefin resin and conductive carbon filler to create a lightweight current collector that maintains structural integrity and electrical conductivity. The composite structure compensates for the inherent weaknesses of resin materials while preserving the weight advantage over metal foils.
Solution Approach 2:
The patent optimizes the composition parameters of the resin current collector, specifically controlling the conductive carbon filler content and surface area, to achieve a balance between weight reduction and cycle characteristic improvement.
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 controlled surface area of the conductive carbon filler in the resin current collector reduces decomposition currents, enhancing the cycle characteristics and durability of lithium ion batteries while maintaining a suitable electrical resistance for efficient battery performance.
Implementation Method 1
a resin current collector which includes a polyolefin resin and a conductive carbon filler
Implementation Method 2
the generation of the (oxidative) decomposition current can be reduced by reducing the total surface area of a conductive carbon filler
Data Source
AI summary
To provide means for improving the cycle characteristics in a lithium ion battery. A resin current collector includes a polyolefin resin, and a conductive carbon filler. The total surface area of the conductive carbon filler contained in 1 g of the resin current collector is 7.0 m2 or more and 10.5 m2 or less.