Composite Battery Current Collector for Iron Corrosion Resistance
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Solution Overview
Problem
Secondary batteries using iron-nickel alloy foils as current collectors face issues such as battery impedance increase, performance attenuation, and internal short circuits due to corrosion of iron by electrolytic solution components, limiting their service life and application.
Innovation Solution
A current collector with a first metal layer of elemental iron or iron alloy and a second metal layer of copper, tin, lead, molybdenum, chromium, or nickel, or their alloys, stacked to prevent direct contact of iron with the electrolyte, enhancing strength and reducing corrosion, thereby prolonging the battery's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If iron-nickel alloy foil is used as current collector to reduce cost and improve energy density, then material cost and weight are reduced, but the iron layer corrodes due to direct contact with electrolytic solution, causing battery impedance increase and performance attenuation
Solution Approach 1:
The current collector uses a composite structure with an iron-based substrate layer combined with a protective metal layer (copper, nickel, tin, lead, molybdenum, chromium or their alloys). This composite design maintains the cost and weight advantages of iron while preventing corrosion through the protective layer, thereby extending battery service life without sacrificing manufacturing ease.
2Use of energy by moving object
If iron-nickel alloy foil is used as current collector, then energy density is improved and cost is reduced, but corrosion of iron by electrolytic solution components causes internal short circuits
Solution Approach 1:
A protective metal layer is introduced as an intermediary between the iron-based substrate and the electrolytic solution. This intermediate layer prevents direct contact and chemical reactions between the iron and harmful electrolytic components (water, HF, etc.), thereby eliminating corrosion while preserving the energy density benefits of the iron-based current collector.
3Ease of manufacture
If iron-nickel alloy foil is used as current collector, then production cost is reduced, but performance attenuation occurs due to iron corrosion
Solution Approach 1:
The patent employs a composite current collector structure where an iron-based substrate layer (cost-effective) is combined with a thin protective metal layer. This composite design maintains low production cost while the protective layer prevents performance attenuation by blocking corrosion, thereby extending the operational duration and maintaining battery performance over time.
Data Source
AI summary
A current collector, comprising a base layer, a first metal layer, and a second metal layer are disclosed. The first metal layer is disposed on at least one surface of the base layer; the second metal layer is disposed on the surface of the first metal layer facing away from the base layer; the first metal layer comprises elemental iron or an iron alloy; the second metal layer comprises at least one of a metal layer formed by any one of copper, tin, lead, molybdenum, chromium and nickel, an elemental metal stack formed by any two or more of the elements, and an alloy layer formed by any two or more of the elements. A preparation method for the current collector, and a secondary battery and an electric device are disclosed.