Electric vehicle battery covers pose unique sealing challenges in the automotive industry. The significant size of the sealing perimeter, the materials and size of the seal mating hardware, and the aggressive performance requirements (physical and chemical) all play a crucial role in the design of this critical seal. For fully electrified vehicles, battery seals run the full circumference of the vehicle. This large seal is imperative to the performance, life, and functionality of the battery which can result in costly repairs and is the most expensive item to replace on an electric vehicle.
With these exacting obstacles in mind, many manufacturers are looking for options on how to seal this critical joint. Two common methods are extruded and spliced homogeneous rubber gaskets and dispensed form in place gaskets (FIP). Deciding which is best requires some evaluation of the pros and cons of each strategy.
Extruded gaskets have many benefits. Parker’s vehicle electrification experts can design and engineer a custom extruded cross-section, providing the exact force needed to maintain a seal and keep closure force low with our innovative hollow profiles. Parker’s O-Ring & Engineered Seals Division offers extruded designs in a wide variety of materials to ensure that long term durability, sealing tests, and flammability requirements can be achieved. The extruded gasket sealing strategy often employs a cast or machined groove on the battery cover. If the design requirements do not permit a groove to be included, Parker has a variety of pressure-sensitive adhesives (PSAs) that can hold the gasket in place.
Other benefits include:
Custom design for your application
Offered in a wide range of materials and temperature ranges
Improved long-term material performance
Application equipment not required
Fully cured material for installation ease
Instant seal upon compression
Seals large gaps
Flexible, accommodating some application movement
Decrease downtime with improved serviceability over form in place gaskets
The one challenge with extruded seals is installation. As electric vehicle annual volumes continue to increase, it is important to be able to install the gaskets easily and quickly. For this reason, Parker has a variety of tools and methodologies to simplify and speed up installation.
Dispensable form in place gaskets are often used when the design for manufacturing specs require a high level of automation. Parker has a range of non-conductive ParPhorm form-in-place (FIP) gasket technologies available.
When evaluating which technology to utilize, customers should recognize that FIP gaskets will require an investment in automation equipment to apply correctly at high volumes. This would include robotics and ample floor space. Additionally, the nature of FIPGs require higher cleanliness on the mating surfaces to ensure that the gasket adheres to the flange adequately. In application, some FIPGs have higher compression set characteristics that lead to less long-term durability of the flange that if not accounted for could lead to failure. Another factor when considering FIPG materials, is the in-line cure time that can be prohibitive depending on your production process. Finally, many battery manufacturers require that the gasket be easily serviceable so that mechanics can open and close the cover as needed over the life of the vehicle. FIPGs adhere to the cover in such a way that makes removing the gasket more difficult than an extruded or molded seal and could complicate the serviceability of the joint.
Sealing the electric vehicle battery perimeter is critical. Parker’s engineering experts are here to guide you through the decision-making process, customizing a sealing strategy that works best for your requirements. Whether you choose extruded, form-in-place or some other alternative, contact our engineering team today to help. Visit us online and chat directly with an engineer today.
This blog was written by Miles Turrell, electric vehicle applications engineer, Engineered Materials Group