When the battery cover is joined to the tray and the EV battery is ready to use, there is one last step to consider: protecting the battery from corrosion in the long term – especially at critical spots such as joints and trim edges. This can be done with special different corrosion protection materials. By choosing the right application technology, manufacturers can save material, avoid manual rework and masking while maintaining serviceability for repairs.
At the end of the battery manufacturing process, the critical areas of the battery need to be sealed to avoid corrosion. State-of-the-art battery designs have many surface breaks, trim edges, and joining elements. For example, mechanical cover-to-tray joining can cause slight damage to the lid’s coating. At these spots, moisture and contamination from splash water, salt water and break abrasion can enter, and there is a high risk for corrosion.
Application challenges on the battery surface
The application process at the surface of the battery with its many contours, edges, and joints is challenging. Common manual or automated spray applications lead to manual rework, masking effort and material waste. This affects the productivity and the quality of the corrosion protection process. On top of that, serviceability aspects may need to be considered. If the joining elements are covered with material, loosening the screws for repair or recycling is difficult.
Materials and application technologies for corrosion protection
A current approach is the application of a MS Polymer material to protect these areas. Suitable application technologies here are flat stream and swirl. The choice of application technology depends on the customers’ requirements, such as bead geometry, application areas or production processes.
A new trend that is coming up is to use special waxes for corrosion protection. These waxes do not cure completly and can be removed. This is particularly advantageous when it comes to servicing the battery later. Waxes can also be applied with flat stream technology. At Atlas Copco, we have also transferred an innovative PVC application technology from paint shops to corrosion protection with wax: IDDA.Seal.
Pinpoint protection of battery cover joints and edges
IDDA.Seal is an intelligent and dynamic drop application. Every single droplet can be controlled individually. This allows for the highest precision and a fully flexible bead geometry. The bead width and thickness can be perfectly adjusted to the customers’ requirements. You can apply the material as thinly and precisely as possible and use only as much material as necessary. From PVC applications we know, that IDDA has up to 40 % less material demand compared to flat stream. In addition, manual rework and material usage are cut to a minimum. For example, the head of the joining element can be omitted, which allows clean loosening of the screw for repairs. Compared to conventional sealing technologies, IDDA is much more flexible in terms of application speed, distance, and angle. This improves accessibility, enables shorter application times, and increases productivity.
Advantages of an IDDA application for the corrosion protection process
- Fast and efficient application of corrosion material exactly where you need it.
- Individual bead designs for highly complex part geometries
- Edge sharp application, no overspray, no masking
- Minimizing manual rework and material use
- Enabling serviceability for repairs
- Avoiding long-term warranty cost due to corrosion problems.
Robot guidance for precise application despite deviations
To compensate for deviations, the application system can be combined with an ISRA VISION robot guidance solution. The MONO2.5D sensor measures customer-specific features such as holes, edges, corners, or surfaces. We ensure that position deviations of the battery tray are considered before starting the application. The application starts precisely at the right position to achieve maximum process accuracy.
Conclusion
With our broad portfolio of joining and application technologies and our holistic process competence, we find the right solution for your EV battery assembly challenge. In our global Innovation Centers, we can carry out extensive tests and perfectly match material, application technology, and vision solution to your production requirements.
The IDDA.Seal application technology is flexible in application distance, speed, and angle.
IDDA.Seal allows a fully flexible bead geometry. The head of the joining element can be omitted, which allows clean loosening of the screw for repairs.
Corrosion protection in EV battery assembly is crucial. With IDDA.Seal wax is applicated while the head of the joining element is omitted for full repairability .
