3D Electrode Electron Directing Members Silicon Expansion
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Solution Overview
Problem
Lithium-ion batteries using carbon-based electrodes suffer from low energy density and rapid capacity fade due to the volume expansion of silicon active materials, leading to electrode delamination, increased internal resistance, and reduced cycle life.
Innovation Solution
A three-dimensional electrode structure with electron directing members extending from the current collector, configured to direct electron flow vertically through the active material layer, which maintains conductive pathways and restricts silicon expansion to two dimensions, reducing particle cracking and internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is added to active materials to increase lithium storage capacity, then energy density is improved, but rapid capacity fade and poor cycle life occur due to volume expansion
Solution Approach 1:
The patent introduces a three-dimensional electrode structure with vertically extending electron directing members that create conductive pathways in the vertical dimension. This dimensional transformation allows electrons to travel directly from the current collector through the active material layer to the separator, bypassing horizontal pathways that would otherwise be disrupted by silicon expansion. The vertical conductive channels maintain electrical connectivity even when silicon particles expand and crack, thereby preserving cycle life while enabling high lithium storage capacity.
2Quantity of substance
If silicon active materials are used to increase capacity, then energy density improves, but electrode delamination and particle cracking occur due to massive volume expansion
Solution Approach 1:
The electrode is segmented into distinct functional components: current collector, vertically extending electron directing members, active material layer, and separator. The electron directing members act as independent structural elements that maintain conductive pathways separately from the expanding silicon particles. This segmentation allows the silicon to expand freely in the horizontal plane without compromising the overall electrode structure, as the vertical electron directing members remain unaffected by the lateral expansion forces.
Solution Approach 2:
The electron directing members function as flexible conductive pathways that can accommodate the volume expansion of silicon particles. These members extend vertically through the active material layer and maintain their structural integrity and electrical conductivity even when surrounding silicon particles expand and crack. The flexible nature of these thin film structures allows them to bend and deform with the expanding particles while maintaining continuous electron transport paths.
3Ease of manufacture
If conventional two-dimensional electrode structure is used, then manufacturing is simple, but electron transport pathways are disrupted leading to increased internal resistance
Solution Approach 1:
The patent transitions from a conventional two-dimensional planar electrode structure to a three-dimensional structure with vertically extending electron directing members. This dimensional enhancement creates dedicated vertical conductive pathways that are independent of the horizontal electron transport paths in the active material layer. The vertical members provide direct electron transport routes from the current collector through the active material to the separator, maintaining low internal resistance while being compatible with existing manufacturing processes for applying and drying the active material slurry.
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 three-dimensional electrode structure enhances lithium ion storage capacity, slows the increase of internal resistance, and extends battery life by maintaining vertical conductive pathways and restraining silicon expansion, thereby improving energy density and durability.
Implementation Method 1
electron directing members extending from a surface of the current collector and configured to direct electron flow along a layered direction of the electrode
Implementation Method 2
each electron directing member having a perimeter edge attached to a surface of the current collector with a polymer binder
Data Source
AI summary
A battery has a three dimensional electrode including a current collector, electron directing members, each electron directing member having a perimeter edge attached to a surface of the current collector with a polymer binder, the electron directing members extending from the surface of the current collector and configured to direct electron flow along a layered direction of the electrode, an active material layer on the current collector and a separator. The electron directing members extend into the active material layer and having a free end in spaced relation to the separator.