Composite Positive Electrode Plate for Low-Resistance Li-Ion Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high mass and volumetric energy density, as well as maintaining good electrochemical performance and safety, due to limitations in current collector materials and processing vulnerabilities.
Innovation Solution
A positive electrode plate with a composite current collector featuring a thin conductive layer and a polymer support layer, combined with a conductive primer layer and a binder-rich electrode active material layer, which includes a mix of small and large particle active materials to enhance conductivity, reduce internal resistance, and improve nail penetration safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic current collector with a metal coating layer is used to reduce weight and increase energy density, then mass energy density is improved, but processing performance and electrochemical performance deteriorate
Solution Approach 1:
The patent uses a composite current collector structure consisting of a polymer support layer (providing mechanical strength and light weight) combined with a thin metal conductive layer (providing electrical conductivity). This composite structure achieves both weight reduction and maintained electrochemical performance by optimizing the synergistic relationship between the polymer and metal components.
Solution Approach 2:
The patent optimizes the thickness of the metal conductive layer within a specific range (30 nm to 3 μm) to achieve the right balance between electrical conductivity and weight reduction. By precisely controlling this parameter, the current collector maintains sufficient conductivity while minimizing weight, avoiding the performance degradation associated with thicker metal layers.
2Weight of moving object
If the conductive layer is made thinner to reduce weight and improve energy density, then mass energy density is improved, but the conductive layer becomes more vulnerable to damage during processing
Solution Approach 1:
The patent combines the thin metal conductive layer with a polymer support layer to form a composite structure. The polymer layer provides mechanical strength and protection to the fragile thin metal layer during processing, while the metal layer maintains sufficient electrical conductivity. This composite approach allows the metal layer to be extremely thin without compromising overall structural integrity.
Solution Approach 2:
The polymer support layer acts as a protective cushion for the thin metal conductive layer before and during processing operations. This pre-existing protective structure prevents damage to the vulnerable thin metal layer during handling, rolling, and assembly operations, eliminating the need for thicker metal layers for mechanical protection.
3Weight of moving object
If a thin conductive layer is used to improve energy density, then mass energy density is improved, but internal resistance and polarization increase
Solution Approach 1:
The patent optimizes the metal layer thickness within a specific range (30 nm to 3 μm) to achieve sufficient electrical conductivity while minimizing weight. This parameter optimization ensures that the thin metal layer maintains adequate conductivity to support electrochemical reactions without excessive internal resistance or polarization.
Solution Approach 2:
The composite structure of polymer support layer and metal conductive layer provides both mechanical integrity and electrical conductivity. The polymer matrix provides a stable substrate that supports the thin metal layer, ensuring consistent electrical contact and reducing resistance variations that would occur with a standalone thin metal layer.
Data Source
AI summary
This application relates to the battery field, and specifically, to a positive electrode plate, an electrochemical apparatus, and an apparatus. The positive electrode plate in this application includes a current collector and an electrode active material layer disposed on at least one surface of the current collector, where the current collector includes a support layer and a conductive layer disposed on at least one surface of the support layer. A single-sided thickness D2 of the conductive layer satisfies 30 nm≤D2≤3 μm. A thickness D1 of the support layer satisfies 1 μm≤D1≤30 μm. The support layer is made of a polymer material or a polymer composite material. The electrode active material layer includes electrode active materials, a binder, and a conductive agent.