Ion-Permeable Composite Current Collectors Without Li Pre-Doping
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Solution Overview
Problem
Conventional methods for producing porous Al and Cu foils for Li-ion batteries are expensive and suffer from poor mechanical properties, leading to issues with electrode uniformity and safety concerns due to the use of Li pre-doping, which increases production costs and risks of fires and Li dendrite formation.
Innovation Solution
The use of ion-permeable composite current collectors with a thickness below 20 microns and pores occupying 1-20% of the cross-sectional area, along with a sacrificial high-capacity Li composition that provides Li to the electrodes, enhancing mechanical properties and safety while allowing for fast Li-ion transport and uniform electrode construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li pre-doping is used to enhance Li-ion transport, then Li-ion conductivity is improved, but production costs increase and safety risks (fires and Li dendrite formation) worsen
Solution Approach 1:
The patent applies preliminary action by pre-forming pores in the current collector before electrode assembly, which enables fast Li-ion transport without requiring Li pre-doping. The pores are created through controlled electrolytic plating that leaves a porous structure, allowing Li ions to move quickly during the first charge cycle without the safety risks associated with Li pre-doping.
Solution Approach 2:
The patent extracts the harmful element (Li pre-doping) from the system while retaining the beneficial effect (fast Li-ion transport). By using a porous current collector structure instead of Li pre-doped electrodes, the invention removes the safety risks of fires and dendrite formation while maintaining high Li-ion conductivity.
2Weight of moving object
If porous structure is used for current collectors, then weight is reduced and Li-ion transport is improved, but mechanical properties worsen
Solution Approach 1:
The patent uses composite materials by combining metal foil with a porous structure formed through controlled electrolytic plating. The resulting composite current collector maintains the mechanical strength of the metal base while incorporating pores that reduce weight and enhance Li-ion transport. The porous layer is integrated with the metal substrate, creating a composite structure that balances mechanical properties with ion permeability.
3Reliability
If conventional porous foil production methods are used, then porosity is achieved, but manufacturing cost increases
Solution Approach 1:
The patent applies porous materials by using controlled electrolytic plating to create a porous structure directly on the current collector during normal electrode fabrication. This method integrates pore formation into the existing manufacturing process rather than requiring separate, expensive porous foil production steps. The porous structure is formed in-situ through plating conditions that create a controlled pore network.
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
This approach results in improved energy density, reduced production costs, enhanced mechanical properties, and increased safety by minimizing Li dendrite growth and oxidation, while maintaining high uniformity and performance characteristics.
Implementation Method 1
porous Al and Cu current collectors generally allow for a relatively fast Li transport though the electrodes
Implementation Method 2
electrolytic plating is conducted onto a non-sticking substrate
Data Source
AI summary
A Li-ion battery cell, among other materials, components, and techniques, is provided that includes ion-permeable anode and cathode electrodes, an electrolyte ionically coupling the anode and the cathode, a separator electrically separating the anode and the cathode, and a sacrificial, high-capacity Li composition for providing Li to at least one of the electrodes.