Metal Current Collector Coating for Homogeneous Solid-State Battery Anodes
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Solution Overview
Problem
Current methods for producing current collectors and anode materials for solid-state batteries are inefficient, costly, and result in non-homogeneous electrical current densities, leading to issues like dendrite formation and limited charging/discharging capabilities.
Innovation Solution
A method involving spraying molten or heated metal particles onto a solid ion-conducting substrate to form a metal layer, which adapts to the substrate's surface contour, creating a homogeneous electrical current density and enabling anode-free designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rolling processes or electrolytic refining are used to produce copper foils, then sufficient thickness and strength are achieved, but the overall weight of the current collector increases and material usage is inefficient
Solution Approach 1:
The patent applies plasma spraying technology to deposit copper particles in a molten or semi-molten state, creating a porous yet mechanically robust structure. This parameter change in deposition method allows achieving sufficient strength with reduced material thickness (1-10 μm vs. conventional 20 μm), thereby reducing weight while maintaining mechanical integrity
Solution Approach 2:
The plasma-sprayed copper layer inherently forms a porous structure that provides both mechanical strength and high surface area for lithium deposition. The porosity allows the layer to be thinner than conventional foils while maintaining structural integrity, directly addressing the weight reduction goal without sacrificing strength
2Weight of moving object
If plastic films are used as current collectors, then weight is reduced, but the specific electrical conductivity is poorer, limiting maximum electrical currents
Solution Approach 1:
The patent creates a composite structure by depositing copper particles onto plastic film substrates. The copper plasma-sprayed layer provides high electrical conductivity (superior to plastic), while the plastic substrate maintains low weight. This composite approach combines the advantages of both materials, achieving weight reduction without sacrificing electrical conductivity
Solution Approach 2:
The copper coating is applied locally on the plastic film where electrical conductivity is needed, rather than using bulk copper throughout. This localized application maintains the low weight advantage of plastic while providing high conductivity only in the functional areas, optimizing the weight-conductivity trade-off
3Use of energy by moving object
If thin ceramic separators are used, then ionic conductivity is improved, but the separators are susceptible to mechanical destruction under contact pressure
Solution Approach 1:
The patent sprays copper particles in a molten or semi-molten state which, upon solidification, penetrates into the pores and surface irregularities of the ceramic separator. This parameter change in particle state during deposition creates a mechanically interlocked structure that strengthens the ceramic without adding significant thickness, maintaining ionic conductivity while improving mechanical robustness
4Manufacturing precision
If sputtering technology is used to deposit copper layers, then homogeneous coverage is achieved, but the deposition speed is extremely slow (nm/min)
Solution Approach 1:
The patent replaces the slow physical vapor deposition process of sputtering with plasma spraying, which uses thermal energy to melt and propel copper particles at high velocity. This substitution of deposition mechanism increases the deposition rate from nm/min to μm/min or mm/min while still achieving homogeneous coverage through the kinetic energy distribution of the sprayed particles
5Manufacturing precision
If atomic layer deposition (ALD) is used, then conformal coating on complex geometries is achieved, but the process is slow and μm-range thicknesses are difficult to realize on large scale
Solution Approach 1:
The patent uses plasma spraying with controlled particle temperature and velocity parameters to achieve conformal coating on complex geometries. The molten or semi-molten particles adapt to surface contours upon impact, providing conformality similar to ALD but at much higher deposition rates suitable for large-scale production of μm-thick layers
6Use of energy by moving object
If rigid metallic copper foil is pressed onto jagged ceramic separator surface, then electrical contact is established, but the ceramic separator breaks due to low thickness
Solution Approach 1:
The patent sprays copper particles in a molten or semi-molten state which, upon solidification, conforms to the jagged surface of the ceramic separator. This parameter change from solid to molten state during deposition allows the copper to adapt to surface irregularities, establishing electrical contact without requiring high contact pressure that would break the thin ceramic separator
7Area of stationary object
If polishing is used to increase electrical contact surface, then contact area is improved, but the process is very cost-intensive and time-consuming
Solution Approach 1:
The patent applies copper particles in a molten or semi-molten state before final assembly, allowing the copper to naturally conform to and fill surface irregularities of the ceramic separator. This preliminary action of adaptive deposition eliminates the need for subsequent polishing operations, reducing manufacturing cost and time while achieving maximum contact surface area
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 method allows for the production of anode-free batteries with high charging and discharging capabilities, reducing material usage and avoiding defects like voids and dendrites, while being cost-effective and suitable for industrial-scale production.
Implementation Method 1
spraying metal particles which are at least partially molten, or solid metal particles which are heated along the spray path, and/or by their impact velocity on the solid ion-conducting substrate, to a temperature which is higher than the melting temperature of the metal particles, wherein at least partially molten metal particles are formed; and allowing the at least partially molten metal particles to solidify on the solid, ion-conducting substrate
Implementation Method 2
spraying metal particles along a spray path in the direction of a solid, ion-conducting substrate
Implementation Method 3
a metal layer is formed which is arranged on the solid, ion-conducting substrate... the metal layer... adapts to the substrate's surface contour
Data Source
AI summary
The invention relates to a method for forming a metal layer (i.e., a metal electric current conductor) on the surface of a solid ion-conducting substrate (for example, a lithium-ion secondary battery or a sodium-ion secondary battery), to a substrate which can be produced using the method, and to an anode-free battery. The method according to the invention allows parts of solid-state electrolyte batteries (e.g., the anode side of a solid-state electrolyte battery) to be provided in an industrially relevant scale in a quick, simple, and inexpensive manner, said parts being characterized by a homogenous electric current density and a suitability for high maximum charge and discharge currents.