Composite Electrode Plate with Graded Conductive Layer Distribution
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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, which can lead to poor conductivity and mechanical issues, resulting in performance degradations and safety concerns.
Innovation Solution
The electrode plate features a composite current collector with a support layer and a conductive layer of specific thickness, where the electrode active material layer is divided into inner and outer regions with uneven conductive agent distribution, enhancing conductivity and binding force between the current collector and active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a metal-plated plastic current collector is used to reduce weight and increase energy density, then mass energy density is improved, but conductivity and mechanical strength deteriorate
Solution Approach 1:
The patent uses a composite current collector structure consisting of a plastic support layer and a metal plating layer. The support layer provides mechanical strength and light weight, while the metal plating layer provides electrical conductivity. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both weight reduction and maintained conductivity.
Solution Approach 2:
The metal plating is applied selectively on the surface of the plastic support layer rather than using solid metal throughout. This localized application of metal provides conductivity only where needed at the electrode interface, while the bulk plastic material provides light weight and mechanical support, resolving the weight-conductivity trade-off.
2Weight of moving object
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 conductive metal layer is applied only where electrical contact is needed (on the surface facing the electrode active material), rather than throughout the entire current collector thickness. This localized plating provides sufficient conductivity at the interface while minimizing overall metal content and weight.
Solution Approach 2:
The combination of plastic support layer and thin metal plating layer creates a composite structure where each material performs its optimal function - the plastic provides mechanical strength and light weight, while the thin metal layer provides localized electrical conductivity.
3Ease of manufacture
If uniform conductive agent distribution is used in the electrode active material layer, then manufacturing simplicity is maintained, but electron transmission efficiency deteriorates
Solution Approach 1:
The conductive agent is distributed non-uniformly with higher concentration near the current collector interface and lower concentration toward the outer surface. This localized concentration of conductive material optimizes electron transmission at the critical electrode-current collector interface where conductivity is most needed, while reducing overall conductive agent content.
Solution Approach 2:
The conductive agent distribution is optimized in the thickness direction (z-dimension) of the electrode layer rather than uniformly throughout. This vertical gradient in conductive agent concentration creates optimized electron transmission pathways from the active material through to the current collector.
Data Source
AI summary
The electrode plate 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, the conductive layer has a single-sided thickness D2 satisfying: 30 nm≤D2≤3 μm; the electrode active material layer is divided into two regions, an inner region and an outer region in a thickness direction of the electrode active material layer, in which the weight percentage of the conductive agent in the inner region of the electrode active material layer is higher than the weight percentage content of the conductive agent in the outer region of the electrode active material layer, and the conductive agent in the inner region of the electrode active material layer includes at least one of a one-dimensional conductive material and a two-dimensional conductive material.