Lithium-ion battery aluminum foil is a key material used in lithium-ion batteries, primarily serving as the cathode current collector in capacitors.
The role of Lithium-Ion Battery Aluminum Foil is to conduct the battery's current from the electrode to the external circuit. It is usually made of high-purity aluminum alloy due to aluminum's excellent conductivity and mechanical strength.
Functions of Lithium-Ion Battery Aluminum Foil
- 1. Electrical Conductivity: The aluminum foil provides good electrical conductivity, enabling efficient current conduction within the battery.
- 2. Mechanical Strength: The aluminum foil needs to have sufficient mechanical strength to withstand the stress generated during the battery's charge and discharge cycles.
- 3. Chemical Stability: The aluminum foil should possess good chemical stability to resist damage from the internal chemical reactions of the battery.
Surface Treatment of Lithium-Ion Battery Aluminum Foil
Surface etching and roughening of the aluminum (Al) alloy foil used for the cathode current collector of lithium-ion batteries can significantly enhance the battery's charge and discharge performance. The bonding strength between the treated aluminum foil and the active material is greatly improved, leading to a noticeable enhancement in the battery's charge and discharge characteristics.
Lithium-ion Battery Structure
1. Cathode (Aluminum Foil)
Aluminum foil is the only suitable material for the cathode (negative electrode) current collector in lithium-ion batteries, with no feasible substitutes. Aluminum foil is chosen because it offers excellent performance in supporting the cathode material, including high conductivity, corrosion resistance, and mechanical strength.
Thickness Accuracy: The aluminum foil used for the cathode is manufactured with high precision, ensuring that the thickness tolerance is within ±0.5 microns (μm). This precision is crucial for maintaining consistent battery performance and reliable operation.
Function and Benefits: Aluminum foil serves as a current collector, supporting the active cathode material and facilitating effective electron transfer. Its lightweight nature and strong mechanical properties help improve the overall performance and durability of the battery. Additionally, aluminum's corrosion resistance ensures a long life and stable operation of the battery.
2. Anode (Copper Foil)
Copper foil is used as the current collector for the anode (positive electrode) in lithium-ion batteries due to its excellent workability and electrical conductivity.
Material Properties: Copper foil has high electrical conductivity, enabling efficient electron flow and minimizing resistance. This property is critical for the anode's performance as it directly affects the charging and discharging efficiency of the battery.
Function and Benefits: Copper foil supports the anode material, enhancing the battery's charge storage and release capacity. Its high conductivity ensures minimal energy loss during electron transfer, thereby contributing to improved battery performance and efficiency.
Technical Parameters of Lithium-Ion Battery Aluminum Foil
| Alloy | 1235 | 1145 | 1060 | 1070 |
| Temper | H18 | H18 | H18 | H18 |
| Tensible strength | ≥150N/mm | |||
| Elongation | ≥1% | |||
| Thickness/mm | 0.0060 | 0.0070 | 0.0080 | 0.0090 | 0.010 | 0.11 | 0.16 |
| Resistance/(Ω.m) | 0.55 | 0.51 | 0.43 | 0.36 | 0.32 | 0.28 | 0.25 |
Lithium-Ion Battery Aluminum Foil 1050 1070 1235 8011 Chemical Composition
| Elements | Composition% | |||||
| 1235 | 1050 | 1060 | 1070 | 1100 | 8011 | |
| Si | 0-0.65 | 0-0.25 | 0-0.25 | 0-0.2 | 0-1.0 | 0.50-0.90 |
| Fe | 0-0.65 | 0-0.4 | 0-0.35 | 0-0.25 | 0-1.0 | 0.60-1 |
| Cu | 0-0.05 | 0-0.05 | 0-0.05 | 0-0.04 | 0.05-0.2 | 0-0.10 |
| Mn | 0-0.05 | 0-0.05 | 0-0.03 | 0-0.03 | 0-0.05 | 0-0.20 |
| Mg | 0-0.05 | 0-0.05 | 0-0.03 | 0-0.03 | 0-0.1 | 0-0.05 |
| Cr | - | - | - | - | - | 0.05 |
| Zn | 0-0.1 | 0-0.05 | 0-0.05 | 0-0.04 | 0-0.1 | 0-0.10 |
| Ti | 0-0.06 | 0-0.03 | 0-0.03 | 0-0.03 | 0-0.1 | 0-0.08 |
| V | 0-0.05 | 0-0.05 | 0-0.05 | 0-0.05 | - | - |
| Al | Remainder | Remainder | Remainder | Remainder | Remainder | Remainder |
Lithium-Ion Battery Aluminum Foil 1050 1070 1235 8011 Mechanical Properties
| Alloy | Temper | Thickness/mm | Room temperature tensile testing results | ||||
| Tensile strength (Rm) MPa | elongation after break (A100) % | elongation after break (A50) % | |||||
| Single side light aluminum foil | Double side light aluminum foil | Single side light aluminum foil | Double side light aluminum foil | ||||
| 1070 | H18 | ≤0.010 | ≥185 | - | ≥2.0 | - | - |
| >0.010-0.013 | |||||||
| >0.013-0.015 | ≥180 | ||||||
| >0.015-0.020 | ≥175 | ||||||
| 1060. 1050 | ≤0.010 | - | - | - | - | - | |
| >0.010-0.013 | ≥190 | ≥2.5 | ≥3.0 | ||||
| 1060, 1050 | >0.013-0.015 | ||||||
| >0.015-0.020 | ≥185 | ≥2.0 | |||||
| 1235 | ≤0.010 | - | - | - | - | - | |
| >0.010-0.013 | ≥180 | ≥2.0 | |||||
| >0.013-0.015 | ≥185 | ||||||
| >0.015-0.020 | ≥175 | ||||||
| 1100 | ≤0.010 | ≥230 | ≥1.0 | ≥2.0 | - | ≥3.0 | |
| >0.010-0.013 | - | ||||||
| >0.013-0.015 | ≥220 | - | |||||
| >0.015-0.020 | ≥2.0 | ||||||
| 8011 | ≤0.010 | ≥180 | ≥1.0 | ≥1.5 | - | - | |
| >0.010-0.013 | - | ≥2.0 | |||||
| >0.013-0.015 | |||||||
| >0.015-0.020 | - | - | |||||
Application of Aluminum Foil in Lithium Batteries
Application in Cathode Material
Material: Aluminum Foil
Coating Material: Lithium Iron Phosphate
Advantages: Lithium iron phosphate, used as the cathode material, has excellent stability and a long service life, making it the preferred choice for cathode plate manufacturing.
Battery Production Process
Steps:
Manufacturing Cathode and Anode Sheets: The cathode sheet is made by coating aluminum foil with lithium iron phosphate, and the anode sheet is made by coating copper foil with graphite or lithium titanate.
Winding: The cathode sheet, anode sheet, and separator are wound together to form the battery core.
Assembly: The wound battery core is placed into the battery casing.
Electrolyte Injection: Ensure that the electrolyte fully permeates the battery core.
Vacuum Packaging: Vacuum packaging is performed to ensure the battery's seal and stable performance.
Advantages of Aluminum Foil in the Lithium Battery Field
1. Extending the Lifespan of Lithium-Ion Batteries
- Description: Special aluminum foil has superior physical properties, which can effectively improve the cycle life of lithium batteries.
- Effect: After using special aluminum foil, the cycling function of lithium batteries is significantly enhanced, extending the overall lifespan of the battery.
2. Improving the Consistency of Lithium Batteries
- Description: Special aluminum foil can effectively reduce the internal resistance of the battery and improve the consistency of internal resistance.
- Effect: This improvement in consistency makes the battery's performance more stable under different operating conditions, ensuring more reliable battery performance.
3. Enhancing the Battery's High-Rate Discharge Function
Description: After selecting special aluminum foil, the high-rate discharge capability of lithium batteries is significantly improved, especially under high-rate conditions (greater than 3C).
Effect:
High-Rate Discharge Capacity: Under high-rate conditions, the discharge capacity is increased by more than 15%.
Energy Density Improvement: Even under the same rate, special aluminum foil can improve the energy density of lithium batteries, enhancing the overall performance of the battery.
How to Choose High-Quality Battery Aluminum Foil?
1. Surface Quality
The surface of the aluminum foil should be uniform, clean, smooth, and free of visible roll marks, pits, pinholes, or corrosion marks.
There should be no creases, spots, or bright lines, as these rolling defects may affect the function and appearance of the aluminum foil.
2. Color Uniformity
The surface of the aluminum foil should have no obvious color difference to ensure consistency and stability in battery applications.
3. No Oil Stains or Odor
The surface should be free of oil stains, and there should be no strong oil smell or visible oil spots, as oil stains may affect the adhesion and performance of the aluminum foil.
4. Surface Tension Standard
The surface tension of the aluminum foil should meet the requirements, with a minimum of 32 dynes when tested with a dyne pen. Low surface tension may affect the coating adhesion and battery performance.