Choosing the wrong battery pack gasket can allow water, dust, coolant, and road salt to enter the enclosure, causing corrosion, high-voltage isolation faults, vehicle shutdown, or costly recalls. EPDM is generally the practical choice for water, weather, ozone, and glycol-coolant exposure, while silicone rubber is preferred when wider temperature resistance and long-term elasticity are critical. The final material must still be selected from the actual pack temperature, fluid exposure, compression, fire requirement, and enclosure design.