Finally, all inner electric vehicle (EV) battery components are in position, and the time has come to seal off the battery tray. The cover sealing is necessary to avoid leakages that can reduce the battery performance or present a health hazard. The challenge is to tightly seal the cover while ensuring the serviceability of the battery tray in the future.
Reversible seal for service issues
Humidity and moisture entering the battery tray can damage the EV battery system and cause the battery's performance to deteriorate dramatically, leading to corrosion. On the other side, hazardous toxic gases are produced within the battery that can be harmful if entering the passenger compartment. The conclusion is that the cover needs to be tightly sealed, not allowing anything in or out during the battery´s lifetime. This comes with one exception; the seal must be reversible so the battery can be serviced if necessary.
Our SCA dispensing product line enables sealant to be applied on either the battery cover or tray. Because the battery cannot be exposed to heat, a 1C (one-component) hot butyl material is commonly used for the cover sealing application. Due to its reversible characteristics, future maintenance and battery service are possible. Other material options are 2C (two-component) polyurethane or 2C silicone, all of which do not require oven curing.
Applying hot butyl with SCA dispensing systems
Regardless of the material, the application needs to be uniform. It is particularly important that the beginning and end of the bead are precisely placed to ensure a tight seal.
Hot butyl needs to be heated up to 160 degrees Celsius, requiring a fully heated dispensing system for the highly viscous material to be applied correctly. This is a complex operation for which we have the right experience and solution to offer. Our SCA dispensing systems enable reliable material tempering from pump to meter to applicator, applying the hot butyl with the proper viscosity and pressure, enabling uniform application with a precise start and finish of the bead.
Reducing scrap and rework
Adding an integrated vision system to the cover sealing process enables inline monitoring, inspection, measurement, and online rework, so the level of quality throughout the cover sealing process can be monitored. Something that, in turn, helps reduce scrap and rework but also increases the process stability.
The result of the dispensing system combined with an integrated vision system ensures a perfect tight cover sealing that prevents humidity, moisture ingress, and gas evaporation. All while guaranteeing the battery's serviceability, reducing waste, and minimizing the risk of rework by increasing the stability of the cover sealing process from start to finish.
Watch the video to learn more about our solution:
