Aluminium Battery Electrode Foil for Thin High-Conductivity Collectors
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Solution Overview
Problem
Current battery electrode foils lack high conductivity and mechanical strength while maintaining minimal thickness, which is crucial for efficient lithium-ion accumulator performance.
Innovation Solution
A battery electrode foil made from an aluminium alloy with specific composition (Si: 0.01-0.15%, Fe: 0.02-0.4%, Cu: ≤0.08%, Mn: ≤0.03%, Mg: ≤0.03%, Cr: ≤0.01%, Ti: 0.005-0.03%) and processed through cold rolling without intermediate annealing to achieve intermetallic phases with diameters of 0.1 to 1.0 μm and a density of ≤9500 particles/mm², resulting in high electrical conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the aluminium foil thickness is reduced to minimize weight and improve energy density, then the energy density increases, but the mechanical strength and electrical conductivity deteriorate
Solution Approach 1:
The patent applies composite materials by combining aluminium with specific alloying elements (Si: 0.01-0.15%, Fe: 0.02-0.4%, Cu: ≤0.08%, Mn: ≤0.03%, Mg: ≤0.03%, Cr: ≤0.01%, Ti: 0.005-0.03%) to create an aluminium alloy that maintains high mechanical strength and electrical conductivity even at reduced thickness of 8-20 μm. The intermetallic phases formed by these alloying elements reinforce the matrix structure, enabling the foil to achieve both thinness and structural integrity.
Solution Approach 2:
The patent applies parameter changes by controlling the density of intermetallic phases to ≤9500 particles/mm² with specific diameter lengths of 0.1 to 1.0 μm. This precise control of microstructural parameters optimizes the balance between mechanical strength and electrical conductivity, allowing the foil to maintain high performance at minimal thickness for maximum energy density.
2Quantity of substance
If the aluminium foil thickness is reduced to improve energy density, then the energy density increases, but the electrical conductivity deteriorates
Solution Approach 1:
The patent uses composite materials by incorporating specific alloying elements (Si, Fe, Cu, Mn, Mg, Cr, Ti) in controlled amounts to create an aluminium alloy that maintains high electrical conductivity (>56% IACS) even at reduced thickness. The intermetallic phases formed by these elements are distributed at controlled density (≤9500 particles/mm²) to minimize their impact on electron transport while providing structural reinforcement.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the size (0.1 to 1.0 μm diameter) and density (≤9500 particles/mm²) of intermetallic phases. This optimization ensures that the phases do not excessively scatter electrons, thereby maintaining high electrical conductivity while enabling reduced foil thickness for improved energy density.
3Productivity
If cold rolling is performed without intermediate annealing to reduce processing steps and time, then the productivity increases, but the manufacturing precision and microstructural control become more difficult
Solution Approach 1:
The patent applies preliminary action by carefully selecting the alloy composition before the cold rolling process. The specific ranges of alloying elements (Si: 0.01-0.15%, Fe: 0.02-0.4%, Cu: ≤0.08%, etc.) are predetermined to ensure that during cold rolling without intermediate annealing, the intermetallic phases form with the desired characteristics (density ≤9500 particles/mm², diameter 0.1 to 1.0 μm). This pre-planning of composition enables the subsequent simplified processing.
Solution Approach 2:
The patent applies parameter changes by optimizing the alloy composition parameters to compensate for the lack of intermediate annealing. The specific chemical composition ranges are designed so that the phase transformation and microstructural evolution during continuous cold rolling produce the target microstructure (intermetallic phase density and size distribution) without requiring intermediate heat treatment steps, thereby maintaining both productivity and manufacturing precision.
4Reliability
If the intermetallic phase density is reduced to improve electrical conductivity, then the electrical conductivity increases, but the mechanical strength may deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the intermetallic phase density to a specific range (≤9500 particles/mm²) rather than simply minimizing it. This controlled density, combined with specific phase size (0.1 to 1.0 μm diameter) and alloy composition, creates an optimal balance where there are enough phases to provide mechanical reinforcement through dispersion strengthening, but not so many that they excessively scatter electrons and reduce electrical conductivity. The result is achieving both >56% IACS conductivity and ≥165 MPa tensile strength.
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 foil exhibits electrical conductivity greater than 56% IACS and tensile strength of ≥165 MPa, with improved thermal stability and surface roughness, making it suitable for lithium-ion accumulators as a current collector.
Implementation Method 1
cold rolling is carried out from an initial thickness of at least 1 mm without intermediate annealing
Data Source
AI summary
The invention relates to a battery electrode foil comprising an aluminium alloy, wherein the aluminium alloy has the following composition in % by weight: Si: 0.01-0.15% by weight, Fe: 0.02-0.4% by weight, Cu: ≤0.08% by weight, Mn: ≤0.03% by weight, Mg: ≤0.03% by weight, Cr: ≤0.01% by weight, Ti: 0.005-0, 03% by weight, wherein the aluminium alloy can contain impurities up to a maximum of 0.05% in each case, in total up to a maximum of 0.15%, the remaining % by weight being aluminium, the proportion of aluminium however being at least 99.35% by weight; wherein the battery electrode foil has intermetallic phases with a diameter length of 0.1 to 1.0 μm with a density of ≤9500 particles/mm2. The invention further relates to a method for the production of a battery electrode foil, its use for the production of accumulators, and accumulators containing the battery electrode foil.