Gradient Conductive Resin Current Collector for Li-Ion Batteries
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Solution Overview
Problem
Lithium ion batteries with current collectors containing conductive carbon fillers face issues of increased resistance and unintended large current generation due to heat generation, which existing technologies struggle to mitigate effectively.
Innovation Solution
A current collector design featuring a first conductive resin layer with conductive carbon and a second conductive resin layer containing metal elements like platinum, gold, silver, copper, or titanium, where the volume percentage of the second conductive filler is higher on the first conductive resin layer side, maintaining contact and reducing resistance, and a metal coating layer on the second surface to prevent local deterioration and large current generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resistance value of the second conductive resin layer is lowered to prepare for heat generation, then the reliability is improved, but a large current will be unintentionally generated
Solution Approach 1:
The patent applies local quality by creating a gradient in the volume percentage of the second conductive filler within the second conductive resin layer. Specifically, the volume percentage is higher on the first conductive resin layer side and lower on the second surface side, allowing different regions to serve different functions: the high filler region maintains low resistance under heat, while the low filler region prevents excessive current generation
Solution Approach 2:
The patent changes the parameter of filler distribution from uniform to non-uniform (gradient). By controlling the volume percentage of the second conductive filler to vary across the thickness of the second conductive resin layer, the resistance characteristics are optimized to balance heat resistance and current prevention
2Weight of moving object
If conductive carbon is used as the first conductive filler, then the weight is reduced, but the resistance value increases accompanying heat generation
Solution Approach 1:
The patent uses composite materials by combining conductive carbon in the first conductive resin layer with a metal element (platinum, gold, silver, copper, nickel, or titanium) as the second conductive filler in the second conductive resin layer. This composite structure leverages the lightweight property of carbon while using the superior electrical conductivity and thermal stability of metal to counteract resistance increase under heat
Solution Approach 2:
The second conductive resin layer acts as an intermediary between the first conductive resin layer and the external environment. It mediates the thermal and electrical stresses by providing a transition zone with gradient filler distribution, protecting the conductive carbon-based first layer from excessive heat while maintaining overall conductivity
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 design suppresses the increase in resistance and unintended large current generation, ensuring stable battery performance by maintaining contact between conductive fillers and preventing local active material deterioration.
Implementation Method 1
even if the temperature of the first conductive layer increases and the second conductive resin layer expands accompanying an increase in the temperature
Data Source
AI summary
A current collector for a lithium ion battery includes a first conductive resin layer and a second conductive resin layer. The first conductive resin layer includes a first conductive filler. The second conductive resin layer is formed on the first conductive resin layer and includes a second conductive filler. The first conductive filler is a conductive carbon. The second conductive filler contains at least one kind of metal element selected from the group consisting of platinum, gold, silver, copper, nickel, and titanium. A volume % of the second conductive filler in the second conductive resin layer on a first surface side, which is a first conductive resin layer side, is higher than that on the second surface side that is opposite to the first conductive resin layer.