China Battery Aluminum Foil Suppliers - High-Purity Current Collector Factory for Lithium-Ion Batteries

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China Battery Aluminum Foil Suppliers - High-Purity Current Collector Factory for Lithium-Ion Batteries

Battery aluminum foil is an essential current collector material specifically engineered for lithium-ion batteries (LIBs), acting as the foundation for the positive electrode active material. This product boasts an ultra-thin design, high purity, exceptional conductivity, and outstanding mechanical properties. These characteristics are crucial as they directly impact the energy density, cycle life, and safety performance of lithium-ion batteries. Our battery aluminum foil is widely utilized in power batteries for new energy vehicles (NEVs), energy storage systems (ESS), and consumer electronics batteries. As a key component in the global new energy industry chain, our factory in China is committed to supplying high-quality battery aluminum foil to meet the growing demand for innovative energy solutions

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Product Description

Core Performance Characteristics

Battery aluminum foil differs from conventional aluminum foils due to its strict performance requirements tailored to battery operating conditions. Its key characteristics are as follows:

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Ultra-high Purity The aluminum content typically exceeds 99.9% (3N) and can reach up to 99.99% (4N) for high-end power batteries. High purity minimizes impurity elements (such as Fe, Si, Cu) that could cause side reactions in the battery, ensuring electrochemical stability.
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Ultra-thin Thickness with Uniformity Common thickness ranges from 4 μm to 20 μm, with 6 μm, 8 μm, and 12 μm being the most widely used specifications. The thickness deviation is controlled within ±0.3 μm to ensure uniform current distribution and avoid local overheating.
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Excellent Conductivity The electrical conductivity is ≥35 MS/m, which reduces the internal resistance of the battery and improves charge-discharge efficiency. High conductivity is particularly crucial for high-rate discharge scenarios like NEVs.
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Superior Mechanical Properties It has high tensile strength (≥150 MPa for 8 μm foil) and good elongation (≥3%), enabling it to withstand the stress of electrode coating, rolling, and battery cycling without cracking or breaking.
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Flat Surface & Strong Adhesion The surface roughness (Ra) is controlled between 0.1 μm and 0.5 μm, ensuring strong adhesion with positive electrode active materials (e.g., lithium cobalt oxide, lithium iron phosphate) and preventing active material shedding during cycling.
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Electrochemical Stability It remains stable in the high-potential environment of the lithium-ion battery positive electrode (3.0–4.5V vs. Li/Li⁺) without undergoing oxidation or dissolution, ensuring long battery cycle life.

Key Manufacturing Process

The production of battery aluminum foil is a high-precision process with strict control over each step to ensure performance consistency. The main steps are as follows:

1

High-Purity Aluminum Ingot Casting: High-purity aluminum ingots (3N–4N) are melted and cast into aluminum coils through continuous casting and rolling, with strict control of impurity content during the casting process.
2

Hot Rolling: The cast aluminum coils are hot-rolled to a thickness of 2–5mm, refining the grain structure and improving mechanical properties.
3

Cold Rolling: This is the core step to achieve ultra-thin thickness. Through multiple passes of cold rolling (with intermediate annealing to eliminate work hardening), the aluminum coil is gradually thinned to the target thickness (4–20 μm). The rolling speed, pressure, and annealing temperature are precisely controlled to ensure thickness uniformity.
4

Surface Treatment: A thin layer of oxide film is formed on the surface through chemical treatment or electrochemical oxidation, enhancing the adhesion with active materials and improving corrosion resistance.
5

Slitting & Cutting: The large-width aluminum foil is slit into rolls of specific widths (matching battery cell sizes) and cut into sheets of required lengths. Edge burrs are strictly controlled to avoid piercing the battery separator.
6

Quality Inspection: Key indicators such as thickness, purity, conductivity, tensile strength, surface roughness, and flatness are comprehensively inspected using precision instruments to ensure compliance with battery-grade standards.

Key Specifications & Application Fields

As the core positive current collector of lithium-ion batteries, battery aluminum foil is widely used in various fields driven by the rapid development of new energy industries:

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New Energy Vehicles (NEVs) It is the main current collector for power batteries of passenger cars, commercial vehicles, and two-wheelers. For example, 8 μm–12 μm aluminum foil is used in ternary lithium and lithium iron phosphate power batteries, contributing to high energy density and long cycle life.
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Energy Storage Systems (ESS) Applied in stationary energy storage (grid-connected energy storage, off-grid power supply) and portable energy storage (outdoor power stations). Its stable mechanical and electrochemical properties ensure the reliability of energy storage systems over long-term operation.
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Consumer Electronics Used in batteries for smartphones, laptops, tablets, and wearable devices. Ultra-thin aluminum foil (4 μm–6 μm) is adopted to reduce battery thickness and increase energy density, meeting the lightweight and miniaturization needs of consumer products.
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Other Fields Applied in special batteries such as aerospace batteries, medical equipment batteries, and power tool batteries, where high purity and stability are required.

Advantages Over Alternative Materials

In lithium-ion battery positive current collectors, battery aluminum foil has irreplaceable advantages compared to alternative materials such as copper foil and stainless steel foil:

Alternative Material	Advantages of Battery Aluminum Foil	Key Reason
Copper Foil	Lower cost (about 1/3 of copper foil), stable in high-potential environments, lighter weight	Copper foil is prone to oxidation at high potentials (positive electrode), while aluminum foil forms a stable oxide film for protection; aluminum has lower market price than copper.
Stainless Steel Foil	Better conductivity (35 MS/m vs. 15 MS/m of stainless steel), lighter weight (density 2.7g/cm³ vs. 7.9g/cm³ of stainless steel), lower internal resistance	Stainless steel has high resistivity, which increases battery internal resistance; its high density reduces battery energy density.
Titanium Foil	Much lower cost (about 1/10 of titanium foil), easier processing, and mature industrial chain	Titanium foil is expensive and difficult to produce in ultra-thin specifications, making it unsuitable for large-scale battery applications.

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Frequently Asked Questions (FAQ)

?What is the standard thickness of battery aluminum foil used in lithium-ion batteries?

Battery aluminum foil commonly ranges from 4 μm to 20 μm in thickness. The most widely used specifications are 6 μm, 8 μm, and 12 μm. For consumer electronics such as smartphones and laptops, ultra-thin foil of 4 μm–6 μm is preferred, while 8 μm–12 μm is standard for NEV power batteries and energy storage systems.

?Why is aluminum foil used as the positive current collector instead of copper foil?

Aluminum foil is preferred for the positive current collector because it remains electrochemically stable at the high operating potentials of the positive electrode (3.0–4.5V vs. Li/Li⁺). Copper foil would oxidize and dissolve under these conditions. Additionally, aluminum is significantly lighter and less expensive than copper, contributing to higher energy density and lower battery costs.

?What purity level is required for battery-grade aluminum foil?

Battery-grade aluminum foil typically requires a minimum purity of 99.9% (3N). For high-end power batteries with demanding performance requirements, 99.99% (4N) purity is specified. Higher purity reduces impurity elements such as Fe, Si, and Cu, which could trigger unwanted side reactions and degrade battery performance over time.

?How does the surface quality of aluminum foil affect battery performance?

Surface quality directly impacts the adhesion between the aluminum foil and the positive electrode active materials (e.g., lithium cobalt oxide, lithium iron phosphate). Surface roughness (Ra) is controlled between 0.1 μm and 0.5 μm to maximize bonding strength, prevent active material shedding during charge-discharge cycling, and maintain consistent electrochemical performance throughout the battery's lifespan.

?What are the main quality inspection criteria for battery aluminum foil?

Comprehensive quality inspection covers multiple key indicators: thickness and thickness deviation (±0.3 μm), aluminum purity, electrical conductivity (≥35 MS/m), tensile strength (≥150 MPa for 8 μm foil), elongation (≥3%), surface roughness (Ra 0.1–0.5 μm), flatness, and edge burr control. All parameters must comply with battery-grade standards before the foil is approved for use in battery manufacturing.

?Can battery aluminum foil be used in energy storage systems as well as electric vehicles?

Yes. Battery aluminum foil is widely used in both applications. In energy storage systems (ESS), it is applied in grid-connected stationary storage, off-grid power supply, and portable outdoor power stations. Its stable mechanical and electrochemical properties ensure reliable long-term operation. In NEVs, it serves as the current collector in both ternary lithium and lithium iron phosphate power batteries, supporting high energy density and extended cycle life.

Product Detail

China Battery Aluminum Foil Suppliers - High-Purity Current Collector Factory for Lithium-Ion Batteries

Product Description

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Product Detail

China Battery Aluminum Foil Suppliers - High-Purity Current Collector Factory for Lithium-Ion Batteries

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