Lithium-Ion Electrode Conductive Path for Thick Active Layers
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Solution Overview
Problem
Increasing the thickness of lithium ion battery electrodes to enhance capacity results in a higher proportion of active materials far from the current collector, leading to poor electron conductivity due to the low conductivity of active materials, which hinders the effective use of increased active material amounts.
Innovation Solution
Incorporating a conductive path made of electronically conductive material within the electrode to connect the active material particles to the current collector, ensuring efficient electron flow, even at increased thicknesses of 150 to 5000 μm, by using conductive fibers or foamed resin with high conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode thickness is increased to enhance capacity, then the proportion of active materials increases, but the electron conductivity deteriorates due to the low conductivity of active materials located far from the current collector
Solution Approach 1:
The patent introduces a conductive member as an intermediary substance between the active material particles and the current collector. This conductive member forms a conductive path that mediates electron transfer from active materials located far from the current collector, solving the conductivity problem while maintaining high active material content in thick electrodes.
Solution Approach 2:
The patent segments the electrode structure by introducing a separate conductive member component distinct from the active material particles. This segmentation allows the conductive member to form an independent conductive network that spans the electrode thickness, ensuring electron pathways are established without relying solely on the inherently low-conductivity active materials.
2Productivity
If the electrode thickness is increased to reduce the relative proportion of current collector and separator, then the energy density improves, but the effectiveness of particulate conductive additives diminishes
Solution Approach 1:
The conductive member acts as a mediator that bridges the gap between thick electrode structures and effective conductivity enhancement. Unlike particulate additives that struggle to form continuous pathways in thick electrodes, the conductive member specifically forms a continuous conductive path from active materials to the current collector, maintaining effectiveness even at 150-5000 μm thickness.
Solution Approach 2:
The patent creates a composite electrode structure combining active material particles with a conductive member that has superior electrical conductivity. This composite approach allows the conductive member to form a percolating network throughout the thick electrode matrix, enabling effective electron transport without the limitations of particulate conductive additives alone.
3Quantity of substance
If the electrode thickness is increased to 150-5000 μm, then the capacity increases, but the electron conductivity becomes insufficient without a dedicated conductive path
Solution Approach 1:
The conductive member serves as a dedicated intermediary pathway that enables electron transport across the entire electrode thickness range of 150-5000 μm. This mediator ensures that even active materials located hundreds or thousands of micrometers from the current collector can efficiently transfer electrons through the conductive member's continuous path.
Solution Approach 2:
The patent addresses the thickness dimension by introducing a conductive member that extends through the thickness direction of the electrode, creating a three-dimensional conductive network. This dimensional approach ensures conductivity is maintained throughout the entire thickness, rather than relying on two-dimensional surface-level conductive additives.
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 conductive path enables smooth electron transfer from active materials to the current collector, enhancing the electron conductivity and capacity of lithium ion batteries, even with thicker electrodes.
Implementation Method 1
at least part of the conductive member (A) forms a conductive path that electrically connects the first main surface to the second main surface, and the conductive path is in contact with the active material particles (B) around the conductive path
Data Source
AI summary
The present invention aims to provide an electrode for lithium ion batteries which exhibits excellent electrical conductivity even if its thickness is large. The electrode for lithium ion batteries of the present invention includes a first main surface to be located adjacent to a separator of a lithium ion battery and a second main surface to be located adjacent to a current collector of the lithium ion battery. The electrode has a thickness of 150 to 5000 μm. The electrode contains, between the first main surface and the second main surface, a conductive member (A) made of an electronically conductive material and a large number of active material particles (B). At least part of the conductive member (A) forms a conductive path that electrically connects the first main surface to the second main surface. The conductive path is in contact with the active material particles (B) around the conductive path.