3D Porous Current Collectors for Stack-Type Lithium Battery Electrodes
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Solution Overview
Problem
Lithium batteries face challenges in achieving high energy density and capacity due to irreversible capacity issues associated with non-reactive regions at the uppermost and lowermost electrodes in stack-type electrode assemblies, leading to reduced battery lifespan and performance.
Innovation Solution
Incorporating a 3D porous current collector at the uppermost and/or lowermost electrodes in the stack-type electrode assembly, which reduces irreversible capacity and prevents curving phenomena during manufacturing, while allowing for increased energy density and capacity by including electrode active materials within the porous structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If non-porous current collectors are used in stack-type electrode assemblies, then manufacturing is simpler, but irreversible capacity increases and energy density decreases
Solution Approach 1:
The patent applies porous current collectors with controlled pore structures to replace traditional non-porous current collectors. The porous structure allows electrolyte penetration into the current collector bulk, enabling lithium ion insertion/extraction throughout the entire current collector volume, thereby reducing irreversible capacity and improving energy density while maintaining structural integrity
Solution Approach 2:
The patent employs composite current collector structures combining different materials with complementary properties. The composite design integrates conductive materials with porous frameworks to achieve both electrical conductivity and high surface area for lithium ion interaction, resolving the contradiction between energy density and manufacturing complexity
2Quantity of substance
If 3D porous current collectors are used, then energy density increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent divides the electrode assembly into modular units with standardized interfaces. The 3D porous current collectors are manufactured as pre-formed modules with consistent geometric parameters, allowing precise stacking and assembly. This segmentation approach maintains high energy density while reducing overall manufacturing precision requirements through modular tolerance accumulation
Solution Approach 2:
The patent optimizes key parameters of the 3D porous current collectors including pore size distribution, porosity percentage, and thickness to achieve the desired energy density. By carefully controlling these parameters within specific ranges, the design achieves high energy density while maintaining compatibility with existing manufacturing precision capabilities
3Quantity of substance
If 3D porous current collectors with active materials are used, then capacity increases, but device complexity increases
Solution Approach 1:
The patent designs the 3D porous current collectors to serve multiple functions simultaneously: they act as the current collection substrate, provide additional active material for lithium storage, and facilitate electrolyte distribution. This multi-functionality increases capacity while avoiding the need for separate components, thereby limiting the increase in device complexity
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 use of 3D porous current collectors at the electrodes decreases irreversible capacity, enhances energy density, and improves battery performance, resulting in increased capacity and lifespan compared to batteries without these features.
Implementation Method 1
a 3-dimensional (3D) porous current collector-including electrode is located in an uppermost portion (e.g., top) and/or in a lowest portion (e.g., bottom) in the electrode assembly
Data Source
AI summary
A stack-type electrode assembly includes a lowermost electrode in a lowermost portion of the electrode assembly; an uppermost electrode in an uppermost portion of the electrode assembly; at least one unit stack between the lowermost electrode and the uppermost electrode, the at least one unit stack comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode; and a plurality of separators between the lowermost electrode and unit stack, between the unit stacks, and between the unit stack and the uppermost electrode.