Lightweight material trends in the electric vehicle industry
Reducing vehicle weight is the key to extending the driving range of electric vehicles. As part of this trend, bonding materials are gradually replacing welds and rivets, making it possible to combine aluminum, high-strength steel and composites in the same structure.
According to numerous studies, every 10% reduction in vehicle weight can increase driving range by about 5–7% with the same battery capacity. Since the battery already accounts for a large share of the weight, designers are forced to find ways to lighten the body, chassis and interior.
Why welding falls short
Traditional spot welding works well with steel but struggles when joining aluminum to steel because of differences in melting point and the risk of galvanic corrosion. Carbon fiber composites and reinforced plastics cannot be welded at all. Structural adhesives solve both problems while distributing stress evenly across the entire bonded surface.
Key material groups
Epoxy and polyurethane structural adhesives
Used for body-in-white frames, battery enclosures and load-bearing components. One-part epoxy adhesives cure in the paint oven, while two-part adhesives are suited to room-temperature curing.
Acrylic tapes and structural foams
They replace screws and rivets on trim panels and decorative moldings, saving anywhere from a few hundred grams to several kilograms per vehicle.
| Joining method | Added weight | Joining dissimilar materials | Corrosion resistance |
|---|---|---|---|
| Spot welding | Low | Limited | Requires additional treatment |
| Rivets, bolts | High | Possible | Moderate |
| Structural adhesive | Very low | Excellent | Good, the adhesive isolates the two metals |
Implementation challenges
- Surface preparation and bond line thickness must be controlled.
- Curing time affects line takt time.
- Joints must be designed in from the start and are difficult to change once the design is frozen.
Beyond the body, the lightweighting trend is also spreading to interiors and battery enclosures. Battery enclosures made of composite or thin-wall cast aluminum are sealed with elastic polyurethane adhesive, which keeps water out while still allowing them to be opened for maintenance. Plastic trim panels use structural foam instead of thick stiffening ribs. Each change saves only a few hundred grams, but added up across the whole vehicle the savings can reach tens of kilograms. What matters is evaluating the entire life cycle: bond durability over many years, repairability after a collision and material separation at recycling.
AMS supplies structural adhesives and structural tapes from leading manufacturers. Contact AMS Vietnam to discuss lightweighting solutions for your project.
