O Temper Deep Drawing 8021 Aluminum Foil for Pouch Battery Aluminum Plastic Film – Engineered for Superior Formability and Barrier Integrity | Mingtai Aluminum
Introduction: The Formability Advantage of O Temper 8021 Foil
In the production of lithium‑ion soft pack (pouch) batteries, the aluminum plastic film (APF) must be deep‑drawn into complex, thin‑walled shapes that accommodate the electrode stack and electrolyte. This forming process places extreme demands on the aluminum barrier layer: it must stretch locally by 20–40% without cracking, wrinkling, or developing pinholes. The O temper (fully annealed) 8021 aluminum foil is specifically engineered to meet these demands, delivering exceptional deep drawability while maintaining the absolute barrier integrity required for battery safety and longevity.
8021 aluminum alloy (Al‑Fe‑Si system, Fe 1.2–1.7%, Si ≤0.15%) is the industry standard for soft pack battery encapsulation. When supplied in the O temper (fully annealed, soft state), it offers the highest formability of any temper, combined with excellent corrosion resistance, low pinhole density, and strong composite adhesion.
Mingtai Aluminum (Stock Code: 601677), with nearly 30 years of experience and an annual production capacity exceeding 1.6 million tonnes, supplies premium O temper deep drawing 8021 aluminum foil specifically engineered for pouch battery aluminum plastic film. Our foil is manufactured under IATF 16949 (automotive quality management) and meets the rigorous technical requirements of leading battery manufacturers worldwide.
Why O Temper is Essential for Deep Drawing Pouch Battery Foil
The “O” temper designation indicates a fully annealed, soft state. This is the optimal condition for deep drawing because it provides:
Maximum elongation – O temper 8021 foil delivers elongation of 13–18% for standard grades (up to 22–26% with optimized processing), far exceeding the H18 temper or other work‑hardened states. This high ductility allows the foil to stretch significantly without cracking during pouch formation.
Minimal spring‑back – The low yield strength of O temper reduces elastic recovery after forming, ensuring that drawn pouch shapes retain their intended geometry with high dimensional accuracy.
Uniform grain structure – Mingtai‘s precision annealing process ensures a fine, equiaxed grain structure across the entire coil, providing consistent forming performance from start to finish.
Work‑hardening during forming – As the foil stretches during deep drawing, it naturally work‑hardens, gaining strength in the most stressed areas (corners, sidewalls) without requiring additional heat treatment.
Deep Draw Performance: Cupping Value & Elongation
The deep drawing capability of O temper 8021 foil is quantified by two key metrics:
1. Cupping Value (≥7.3mm)
The cupping (cup drawing) test measures the maximum depth a foil can be drawn into a cup shape without cracking. Mingtai‘s O temper 8021 foil achieves a cupping value of ≥7.3mm (with optimized processing reaching 7.6mm). This is significantly higher than standard aluminum foils and ensures reliable forming for complex battery pouch geometries, including:
3C product batteries – Thin‑walled cavities for smartphones, tablets, and laptops (depth ≥5mm)
Power batteries – Large‑area panels for electric vehicles and energy storage systems
2. Elongation (13–26%)
| Foil Thickness | Typical Elongation (O Temper) | Best Suited For |
|---|---|---|
| 0.025 mm (25μm) | 15–18% | Ultra‑thin consumer batteries, compact designs |
| 0.030 mm (30μm) | 18–22% | Mainstream smartphone/tablet batteries |
| 0.035 mm (35μm) | 20–24% | EV and high‑capacity pouch cells |
| 0.040 mm (40μm) | 22–26% | Large‑format EV and ESS batteries |
With optimized production processes, O temper 8021 foil can achieve tensile strength of 97 MPa and elongation of 22% with a cupping value of 7.6%, meeting the performance level of imported aluminum foils.
Barrier Performance: Absolute Protection Against Moisture and Electrolytes
While O temper prioritizes formability, it does not compromise barrier integrity. The 8021 alloy‘s dense metallic structure provides:
Moisture barrier – Moisture vapor transmission rate ≤0.1 g/(m²·24h), effectively blocking external moisture from entering the battery
Pinhole‑free surface – Pinhole density ≤1 per m² (diameter ≤0.03mm), preventing electrolyte leakage and moisture ingress
Electrolyte corrosion resistance – The dense, stable oxide layer resists degradation from aggressive LiPF₆‑based electrolytes, ensuring long‑term battery stability
Composite Adhesion: Strong Lamination for Reliable Encapsulation
The aluminum plastic film consists of three layers: nylon outer layer, 8021 aluminum middle layer, and CPP (cast polypropylene) inner layer. The aluminum foil must bond tightly with adjacent layers to prevent delamination. Mingtai‘s O temper 8021 foil features:
Ultra‑clean surface – Oil content ≤5 mg/m², surface roughness Ra ≤0.2μm
High peel strength – 180° peel strength ≥3N/15mm, ensuring strong adhesion even under charge‑discharge cycles or temperature fluctuations (-40°C to 85°C)
Puncture & Tear Resistance for Battery Safety
During battery assembly and operation, the aluminum plastic film may encounter external impacts or internal electrode expansion. O temper 8021 foil (H19 temper for higher strength applications) provides:
Tensile strength – 85–105 MPa (O temper); up to 120–160 MPa (H19 temper)
Puncture force – ≥8N, preventing the aluminum layer from being pierced by burrs or external objects
Tear resistance – The refined grain structure prevents crack propagation, ensuring the pouch remains intact even under mechanical stress
Technical Specifications for Pouch Battery Aluminum Plastic Film
| Parameter | 3C Product Batteries | Power Batteries (EV/ESS) |
|---|---|---|
| Alloy | 8021 (Al‑Fe‑Si‑Mn) | 8021 (Al‑Fe‑Si‑Mn) |
| Temper | O | O / H19 |
| Thickness | 0.03 – 0.045 mm (30–45μm) | 0.04 – 0.08 mm (40–80μm) |
| Thickness tolerance | ±0.002 mm | ±0.002 mm |
| Width | 100 – 1,600 mm (customizable) | 100 – 1,600 mm (customizable) |
| Elongation | ≥13% | ≥15% |
| Cupping value | ≥6.8mm | ≥7.3mm |
| Pinhole density | ≤1 per m² (diameter ≤0.03mm) | ≤1 per m² (diameter ≤0.03mm) |
| Moisture vapor transmission rate | ≤0.1 g/(m²·24h) | ≤0.1 g/(m²·24h) |
| Tensile strength (O temper) | 85 – 105 MPa | 85 – 105 MPa |
| 180° peel strength | ≥3N/15mm | ≥3N/15mm |
Quality Assurance for Battery Safety
Mingtai‘s O temper 8021 foil is manufactured under strict quality controls aligned with battery industry requirements:
IATF 16949 certified – Automotive grade quality management, essential for EV and ESS battery supply chains
100% online pinhole inspection – Laser scanners detect any pinhole >0.03mm; coils exceeding the limit are automatically rejected
Precision annealing – Computer‑controlled furnaces ensure consistent O temper properties batch after batch
Mechanical testing – Every batch is verified for tensile strength, elongation, cupping value, and peel strength
Surface cleanliness testing – Oil content and wetting tension are measured to ensure lamination readiness
Why Choose Mingtai for O Temper 8021 Deep Drawing Foil?
Nearly 30 years of aluminum foil experience – Publicly traded company with dedicated battery foil production lines
Proven deep draw performance – Elongation 13–26%, cupping value ≥7.3mm, withstands ≥5mm drawing depth
Ultra‑low pinhole density – ≤1 per m² for absolute barrier integrity
Clean, lamination‑ready surface – Oil content ≤5 mg/m², 180° peel strength ≥3N/15mm
IATF 16949, ISO 9001, ISO 14001 certified – Automotive grade quality management
Flexible ordering – MOQ 3 tonnes; free sample testing available
Fast delivery – 7–45 days to over 150 countries
Conclusion
For battery manufacturers seeking an encapsulation foil that combines superior deep draw formability with absolute barrier integrity, O temper deep drawing 8021 aluminum foil from Mingtai Aluminum delivers exceptional elongation (13–26%), cupping value ≥7.3mm, pinhole density ≤1/m², and reliable composite adhesion. Our precision‑engineered O temper foil ensures that your pouch cells form without cracking, seal without leaks, and maintain barrier integrity for thousands of cycles.
Contact Mingtai Aluminum today for free samples, technical data sheets, or a factory‑direct quotation.
FAQ – O Temper Deep Drawing 8021 Aluminum Foil for Pouch Battery Aluminum Plastic Film
Q1: What is the difference between O temper and H18 temper for pouch battery foil?
A: O temper (fully annealed, soft) provides maximum elongation (13–26%) and formability for deep drawing complex pouch shapes. H18 temper (fully hard) provides higher tensile strength (≥180 MPa) and rigidity for applications where dimensional stability is critical. O temper is the standard choice for aluminum plastic film in pouch batteries.
Q2: What is the cupping value of Mingtai‘s O temper 8021 foil, and why does it matter?
A: Mingtai‘s O temper 8021 foil achieves a cupping value of ≥7.3mm (up to 7.6mm with optimized processing). This measures the maximum depth the foil can be drawn without cracking – a higher value means better deep drawing capability for complex battery pouch shapes.
Q3: What thickness of O temper 8021 foil is recommended for smartphone batteries?
A: For smartphone batteries, 0.030–0.040 mm (30–40 microns) is typical. For EV and ESS batteries, 0.035–0.080 mm (35–80 microns) is recommended depending on cell size and capacity requirements.
Q4: Can Mingtai supply O temper 8021 foil with pinhole density lower than ≤1 per m²?
A: Yes. Mingtai‘s premium grade achieves ≤1 pinhole per m² (diameter ≤0.03mm). For standard applications, ≤5 per m² is available.
Q5: What certifications does Mingtai hold for battery materials?
A: Mingtai is IATF 16949 (automotive quality management), ISO 9001, and ISO 14001 certified. Products comply with RoHS and REACH.
Q6: How is the foil packaged to maintain its quality?
A: Coils are moisture‑proof wrapped with desiccant, edge protectors, and optional PE film interleaving. Cleanroom packaging prevents contamination before lamination.
Mingtai Aluminum – Battery Materials Division
Phone: +86-18776078273
Email: sales@mingtai-al.com
Website: https://m.mingtai-al.com/
Factory Address: Gongyi City Industrial Agglomeration Area, Henan, China
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