How Oxidized Bitumen Improves Battery Sealing
In modern alkaline battery manufacturing, one of the most critical challenges is preventing the leakage of electrolyte, especially in high-performance applications. A specialized grade of oxidized bitumen is used as a sealing compound between the battery gasket and the metal casing to enhance leak resistance. This grade of bitumen, processed through controlled air-blowing techniques, offers strong adhesion properties—particularly to nickel-plated steel surfaces.
Bitumen’s Role in Battery Structure
When applied correctly, oxidized bitumen serves as a semi-rigid sealing layer that effectively bonds to both the gasket and the internal wall of the cell. However, results can vary depending on the surface material. For instance, nickel-plated steel offers a much more stable bonding surface compared to unplated steel. This performance difference has led many battery manufacturers to adopt specific bitumen grades such as 90/15 and 115/15, known for their low penetration and high softening points.
Challenges and Alternatives in Sealant Composition
Earlier attempts to improve battery seals included materials like fatty polyamide resins, or blends of oxidized bitumen and polyamides. These materials, although somewhat effective, suffer from poor bonding under heat or mechanical stress during assembly. The inherent softness and tackiness of some grades, such as 95/25, can lead to deformation or contamination if not applied with precision.
Material Selection Matters
To achieve optimal sealing, manufacturers are now turning to harder and more temperature-resistant grades like 90/40 and 85/40. These offer better structural integrity and resist chemical degradation from alkaline electrolytes. Using the right bitumen type not only ensures tight sealing but also improves the shelf life and safety of the battery.
Balancing Conductivity and Protection
In advanced battery designs, bitumen must be carefully confined to the sealing area. Overspreading can introduce a non-conductive layer between the electrode and the collector, reducing electrical performance. Thus, both material properties and application methods must be optimized. In this context, bitumen grades like 90/10 are used for specialized use-cases where flowability at lower temperatures is needed.
Conclusion: Reliable Bitumen Solutions for Battery Sealing
The use of oxidized bitumen in battery production reflects its versatility and efficiency as a sealing material. By selecting the appropriate grade based on thermal resistance, penetration level, and adhesion to specific metals, battery manufacturers can significantly enhance leak protection and product longevity. For technical support and reliable supply of oxidized bitumen grades, Petro Talla Khalij Fars remains a trusted refinery partner.