The special requirements for fasteners in new energy vehicle models mainly focus on lightweighting, high strength, insulation, corrosion resistance, and anti-loosening performance to cope with the high-voltage environment of the three-electric system, the need for overall vehicle weight reduction, and the challenges of complex operating conditions.
Balancing Lightweighting and High Strength
Due to the large weight of the battery pack, new energy vehicles have higher requirements for overall vehicle lightweighting, and fasteners must achieve "weight reduction without sacrificing strength."
Aluminum alloy, titanium alloy, and high-performance engineering plastics (such as PEEK) fasteners are widely used. Their density is only 1/5–1/3 that of steel, but their strength is comparable to 8.8 or even 10.9 grade steel bolts.
Carbon fiber reinforced composite material fasteners are used in the battery pack structure to achieve the dual goals of weight reduction and fatigue resistance.
High-Voltage Insulation and Electrical Safety
The operating voltage of the three-electric system (battery, motor, and electronic control) generally reaches 400V–800V, and fasteners must have high insulation performance.
The dielectric strength must be >30kV/mm, and the volume resistivity >10¹⁵Ω·cm to prevent galvanic corrosion or short circuits in high-voltage circuits.
PEEK special screws are widely used in electric drive systems, offering 100 times better insulation performance and reducing the risk of vibration loosening by 90%.
Extreme Environment Resistance:
Fasteners must be able to operate in a wide temperature range from -40℃ to 180℃, especially in motor and battery systems.
They must pass tests including ≥500 hours of salt spray testing, UV aging resistance, and thermal cycling shock resistance.
Die-cast aluminum housing connectors utilize surface treatment technologies such as micro-arc oxidation and Dacromet coating to enhance corrosion resistance.
