יתרונות טכניים של חומרי רדיד אלומיניום באריזה של תא סוללה
Driven by the rapid expansion of the new energy industry, demand for lithium batteries continues to escalate. Battery cell packaging plays a decisive role in determining battery lifespan, energy density, and safety performance. Owing to its distinctive physical, כִּימִי, and process compatibility characteristics, aluminum foil has become a core packaging material. Based on standards, data, and application cases, this article systematically explains the properties and process advantages of aluminum foil, providing reference value for industry practitioners and customers.
אֲנִי. Industry Background and Material Requirements for Battery Cell Packaging
1.1 Core Functions of Cell Packaging and Industry Development Trends
The core functions of battery cell packaging include:
- Physical protection: resisting impact, נֶקֶר, and deformation to safeguard internal components
- Environmental barrier: preventing moisture and oxygen ingress to avoid performance degradation
- Sealing and insulation: isolating electrical circuits and preventing short circuits or electrolyte leakage
Lithium battery development is trending toward higher energy density, enhanced safety, longer cycle life, and lightweight design. Consumer electronics emphasize ultra-thin and irregular shapes, power batteries prioritize safety redundancy, and energy storage batteries focus on long-term stability and cost efficiency. Traditional materials struggle to meet these diversified requirements.
Aluminum foil and aluminum-plastic films, due to their lightweight nature, high barrier performance, and processing flexibility, have become the preferred materials for pouch and blade batteries, with continuously increasing market penetration.
1.2 Core Performance Requirements for Cell Packaging Materials
Key performance requirements for packaging materials include:
- ביצועי מחסום גבוהים:
- קצב העברת אדי מים (WVTR) ≤ 0.01 g/m²·day
- קצב העברת חמצן (OTR) ≤ 0.005 cm³/m²·day
- תכונות מכניות: חוזק מתיחה גבוה, הַאֲרָכָה, והתנגדות לנקב
- Stable heat-sealing performance: heat seal strength ≥ 35 N/15 mm
- Electrolyte corrosion resistance
- Lightweight and cost efficiency
- Compliance with environmental regulations such as RoHS
1.3 Comparison of Mainstream Cell Packaging Materials
Current cell packaging materials include metal housings, aluminum-plastic films, and plastic films. A comparison is shown in Table 1.
| סוג חומר | Core Composition | ביצועי מחסום | ביצועים מכניים | Lightweight Level | גמישות עיבוד | Electrolyte Resistance | עֲלוּת | יישומים אופייניים |
|---|---|---|---|---|---|---|---|---|
| Aluminum alloy housing | סגסוגת אלומיניום | מְעוּלֶה | מְעוּלֶה (פְּגִיעָה, compression) | בֵּינוֹנִי (צְפִיפוּת 2.7 g/cm³) | יָרוּד | בֵּינוֹנִי (requires coating) | בינוני-גבוה | Prismatic, cylindrical cells |
| Stainless steel housing | Stainless steel | מְעוּלֶה | מְעוּלֶה (חוזק גבוה) | יָרוּד (צְפִיפוּת 7.9 g/cm³) | יָרוּד | מְעוּלֶה | גָבוֹהַ | High-end power and specialty batteries |
| Aluminum-plastic film | רדיד אלומיניום + ניילון + CPP | מְעוּלֶה (near metal) | טוֹב (התנגדות לנקב, הַאֲרָכָה) | מְעוּלֶה (50% lighter than metal cases) | מְעוּלֶה | מְעוּלֶה | בֵּינוֹנִי (decreasing with localization) | Pouch and blade batteries |
| Plastic film | לְלַטֵף, CPP | יָרוּד | לְמַתֵן | מְעוּלֶה | מְעוּלֶה | לְמַתֵן | נָמוּך | Low-end consumer cells |
Key conclusion:
Aluminum-plastic film, with aluminum foil as the core barrier layer, provides a balanced optimization of key performance indicators, making it highly suitable for pouch and blade batteries. Aluminum foil performance directly determines packaging quality and must be the primary focus in material selection.
II. Core Characteristics of Aluminum Foil for Battery Cell Packaging
Aluminum foil used for cell packaging primarily includes high-purity aluminum foil (1050, 1060 סִדרָה) and aluminum alloy foil (3003 סִדרָה). Through specialized rolling and surface treatment processes, these materials provide critical support for cell packaging performance.
2.1 Fundamental Properties of Aluminum Foil
2.1.1 מאפיינים פיזיים
- קַל מִשְׁקָל: צְפִיפוּת 2.7 g/cm³ (one-third that of stainless steel), improving energy density
- משיכות גבוהה: elongation 8–20%, rollable to ≤ 5 מיקרומטר, מתאים לציור עמוק
- Good thermal conductivity: 237 עם(מ·ק), enhancing thermal stability
2.1.2 מאפיינים כימיים
- Naturally forms a dense 2–5 nm Al₂O₃ oxide layer at room temperature, offering intrinsic oxidation and corrosion resistance
- Chromium-free zirconium or titanium passivation further enhances oxide stability and electrolyte resistance
2.1.3 מאפיינים מכניים
Mechanical performance can be precisely controlled through alloying and rolling processes.
| דרגת סגסוגת | יסודות סגסוגת עיקריים | חוזק מתיחה (MPa) | הַאֲרָכָה (%) | יתרונות מרכזיים | יישומים אופייניים |
|---|---|---|---|---|---|
| 1050 | אל ≥ 99.5% | 70-130 | 5–20 | משיכות מעולה, עמידות בפני קורוזיה | Standard consumer cells |
| 1060 | אל ≥ 99.6% | 70–180 | 8–20 | טוהר גבוה, יכולת עיבוד מעולה | High-end consumer and pouch cells |
| 3003 | Mn 1.0–1.5% | 110–230 | 12–20 | חוזק גבוה, stable forming | Power and energy storage batteries |
2.2 Special Process Requirements for Packaging Aluminum Foil
2.2.1 Ultra-Thin Rolling
Typical thickness ranges from 20–40 μm, while high-end products reach ≤ 5 מיקרומטר. Thickness deviation is controlled within ±4% (high-end ≤ ±2%).
דוּגמָה: Chalco’s 0.005 mm aluminum foil for aluminum-plastic film supports solid-state batteries with energy density > 500 ואט/ק"ג.
2.2.2 טיפול פני השטח
Includes surface cleaning, chromium-free passivation, and nano-coatings (Al₂o₃, SiO₂), improving corrosion resistance and adhesive compatibility while increasing barrier performance by over 10×.
2.2.3 בקרת חריר
לפי GB/T 3198-2020, premium aluminum foil requires pinhole density ≤ 400 יח'מ"ר, while high-end products ≤ 100 יח'מ"ר, achieved via precision rolling and online inspection systems.
III. Technical Advantages of Aluminum Foil in Cell Packaging Manufacturing Processes
3.1 Aluminum-Plastic Film Lamination
Aluminum foil exhibits strong compatibility across dry, תֶרמִי, and dry-thermal lamination processes, achieving peel strength ≥ 15 N/15 mm in high-end applications.
3.2 Deep Drawing Forming
With elongation of 8–20%, aluminum foil supports 5–10 mm deep drawing without cracking. Its smooth surface (Ra ≤ 0.2 מיקרומטר) reduces friction and improves forming efficiency.
3.3 איטום בחום
High thermal conductivity ensures uniform CPP melting. Heat seal strength ≥ 35 N/15 mm (עד 50 N/15 mm), with stable performance at 155 ± 5°C.
3.4 Cutting and Edge Processing
Moderate hardness enables burr-free cutting with dimensional deviation ≤ ±0.1 mm, suitable for automated lines operating at 10–15 m/min.
IV. Core Performance Advantages and Application Validation
4.1 High Barrier Performance
≥ 20 μm aluminum foil achieves WVTR ≤ 0.01 g/m²·day and OTR ≤ 0.005 cm³/m²·day.
מִקרֶה: 30 μm aluminum foil film maintained ≥ 90% capacity after 1000 h at 85°C/85% RH.
4.2 Mechanical Safety Margin
חוזק מתיחה עד 230 MPa, puncture resistance ≥ 300 נ, and excellent performance in drop, compression, and needle penetration tests.
4.3 יתרון קל משקל
Compared with metal housings, aluminum-plastic packaging reduces weight by 50–70%, improving energy density by up to 10%.
4.4 Electrolyte Corrosion Resistance
Chromium-free passivated aluminum foil maintains > 90% peel strength after 7 days at 60°C electrolyte immersion.
4.5 יעילות עלות
Domestic aluminum foil costs ~3–5 RMB/m², significantly lower than imported aluminum-plastic films, with recyclability ≥ 95%.
V. Quality Control and Industry Standards
5.1 Core Quality Control Indicators
| מַד | דְרִישָׁה | תֶקֶן | שיטת בדיקה |
|---|---|---|---|
| סטיית עובי | ≤ ±4% (high-end ≤ ±2%) | GB/T 3198-2020 | Laser thickness gauge |
| Pinhole density | ≤ 400 יח'מ"ר (high-end ≤ 100 יח'מ"ר) | GB/T 3198-2020 | Dark-field imaging |
| איכות פני השטח | Ra ≤ 0.2 מיקרומטר | GB/T 3615-2022 | Roughness measurement |
| תכונות מכניות | מתיחה ≥ 70 MPa, התארכות ≥ 8% | GB/T 228.1-2021 | בדיקת מתיחה |
| מאפייני מחסום | WVTR 0.01 g/m²·day | GB/T 1037-2021 | Permeability testing |
VI. Application Cases and Market Validation
6.1 מוצרי אלקטרוניקה
- Huawei Mate 60 Pro: 1060 רדיד אלומיניום, battery thickness 2.8 מ"מ, energy density 280 ואט/ק"ג
- Apple MacBook: 3003 רדיד סגסוגת אלומיניום, energy density ≥ 300 ואט/ק"ג
6.2 סוללות כוח
- BYD Blade Battery: 3003 רדיד סגסוגת אלומיניום, energy density 180 ואט/ק"ג, enhanced safety
- CATL Qilin Battery: 8 μm composite aluminum foil, energy density 250 ואט/ק"ג
6.3 Energy Storage Batteries
- Residential storage systems: 1060 רדיד אלומיניום, cycle life ≥ 6000 מחזורים, 15-year lifespan
VII. ש&א (שאלות נפוצות)
- How do foil requirements differ by cell type?
Pouch cells favor high-purity foil; blade cells require higher strength alloy foil. - How does foil thickness affect performance?
Thicker foil improves barrier properties but reduces energy density; composite solutions balance both. - Domestic vs imported foil differences?
Key gaps lie in ultra-thin precision, pinhole stability, and surface consistency. - Long-term electrolyte exposure risks?
Mitigated by chromium-free passivation and nano-coatings. - How to verify production line compatibility?
Validate lamination, heat sealing, and cutting performance via pilot trials. - New requirements from solid-state batteries?
דק במיוחד (≤ 5 מיקרומטר), מחסום גבוה יותר, stronger interface compatibility, and vacuum process adaptability.