Electrode plate and electrochemical device
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high mass and volume energy density due to limitations in current collector materials, leading to poor conductivity and mechanical issues, which affect the electrochemical performance and safety of the batteries.
Innovation Solution
The introduction of a composite current collector with a support layer and a conductive layer of specific thickness, along with a conductive primer layer containing one-dimensional or two-dimensional conductive materials, enhances the binding force and conductivity between the current collector and the electrode active material layer, reducing internal resistance and improving electron transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a metal-plated plastic current collector is used to reduce weight and increase energy density, then mass energy density and volume energy density are improved, but processing performance, safety performance, and electrical performance deteriorate
Solution Approach 1:
The patent uses a composite current collector structure consisting of a plastic substrate layer, a metal plating layer, and a conductive coating layer. This multi-layer composite structure combines the lightweight advantage of plastic with the conductivity of metal and the processing performance of the conductive coating, resolving the contradiction between energy density improvement and electrical performance deterioration
Solution Approach 2:
The patent applies different materials and properties to different layers of the current collector: the plastic substrate provides lightweight structure, the metal plating layer provides base conductivity, and the conductive coating layer provides enhanced electrical performance and processing characteristics. Each layer has optimized local properties that collectively resolve the overall performance contradictions
2Quantity of substance
If the conductive layer thickness is reduced to decrease current collector weight, then mass energy density is improved, but conductivity and mechanical strength deteriorate
Solution Approach 1:
The patent employs a composite structure with a thin metal plating layer combined with a conductive coating layer containing conductive polymers and/or metal particles. This composite approach maintains adequate conductivity while allowing the metal layer to be thinner, thus improving mass energy density without sacrificing electrical performance
Solution Approach 2:
The patent changes the composition and structure of the conductive layer by incorporating conductive polymers and metal particles in specific ratios, and by controlling the thickness parameters within optimized ranges. These parameter optimizations enable reduced metal layer thickness while maintaining conductivity requirements
3Reliability
If a conductive primer layer with conductive materials is added to improve binding force and conductivity, then electrical performance is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into the conductive primer layer: it serves as an adhesive layer for binding the electrode active material layer to the current collector, as a conductive layer for improving electrical performance, and as a protective layer. This merging of functions reduces the need for separate layers, thereby limiting the increase in structural complexity while achieving improved electrical performance
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 increases the power performance and reliability of lithium-ion batteries by reducing direct current internal resistance, preventing significant polarization and lithium precipitation during long-term cycling, while ensuring balanced electrical and safety performance.
Implementation Method 1
a conductive primer layer containing a first conductive material and a binder is provided between the current collector and the electrode active material layer, and the first conductive material in the conductive primer layer includes at least one of a one-dimensional conductive material and a two-dimensional conductive material
Data Source
AI summary
The electrode plate according to the present application includes a current collector and an electrode active material layer disposed on at least one surface of the current collector, wherein the current collector includes a support layer and a conductive layer disposed on at least one surface of the support layer, the conductive layer has a single-sided thickness D2 satisfying: 30 nmD23 μm; and a conductive primer layer containing a first conductive material and a binder is provided between the current collector and the electrode active material layer, and the first conductive material in the conductive primer layer comprises at least one of a one-dimensional conductive material and a two-dimensional conductive material. The electrode plate of the present application has good workability, and the electrochemical device including the electrode plate has high energy density, good electrical performance and long-term reliability.