Enhanced Flame-Retardant PA6 for High-Voltage Components in Electric Vehicles Analysis

Enhanced flame-retardant PA6 (Nylon 6) is one of the most widely used key materials in high-voltage components of electric vehicles.

This stems from the three core requirements of the high-voltage system in electric vehicles, which basic PA6 cannot fully meet.

High Voltage Safety Requirements:Electric vehicles typically operate at voltages as high as 400V-800V, posing risks of arc breakdown and short circuits. Materials must have...Excellent flame retardancyPrevent the spread of fire.

High mechanical strength and dimensional stability requirements:High-voltage connectors, housings, and other components need to withstand insertion and extraction forces, vibrations, and impacts, while maintaining shape stability under prolonged high temperatures to prevent loosening or deformation. The basic PA6 lacks sufficient strength and rigidity, and has a low heat distortion temperature.

3. Heat aging requirements:During vehicle operation, the motor and battery generate a significant amount of heat, causing the cabin environment temperature to frequently exceed 100°C, with short-term peaks even higher. Materials must be able to withstand high temperatures for extended periods without degradation.

"Enhanced flame-retardant PA6" is specifically designed to meet these requirements.

“PA6”It offers excellent electrical insulation, chemical resistance, processing flowability, and comprehensive mechanical properties.

Achieved by adding halogen-free flame retardants (usually phosphorus-nitrogen synergistic systems).UL94 V-0The grade (even at a thickness of 0.8mm or thinner) greatly enhances safety.

EnhanceUsually refers to addingGlass Fiber (GF)...significantly improve the material's:

Tensile strength, flexural modulusRigidity

Heat Deflection Temperature (HDT)It can be raised to above 200℃.

Dimensional stabilityReduce the impact of shrinkage rate and moisture absorption.

High-voltage connector

✅Application Components:Shell, sheath, locking mechanism.

Request: Translate the above content into English and output the translation directly without any explanation.High CTI value (compared to the tracking index, usually requiring ≥600V), UL94 V-0 flame retardancy, high rigidity to ensure insertion and withdrawal lifespan, and good dimensional accuracy to ensure sealing.

Material Selection:Usually used15% to 30% glass fiber reinforced flame-retardant PA6。

2. Battery module and pack components

Application components:

✅ Battery module end plate/bracket:Fixed battery cells, which endure substantial binding forces, require high rigidity and strength.

✅ Busbar Insulation Support:Isolate high-voltage conductors, requiring high CTI and flame retardancy.

Battery management system casing and bracket.

Material selection:High glass fiber content (30%-50%) flame-retardant PA6 is commonly used for structural load-bearing components.

3. Charging System

Application Components:

✅ Onboard charger housing and internal bracket.

✅ DC/AC charging gun housing, internal terminal bracket.The charging gun requires excellent tactile feel (surface texture), flame retardancy, impact resistance, and durability for plugging and unplugging.

Material Selection:The shell of the charging gun is often made ofFlame-retardant reinforced PA6Sometimes it is used in combination with materials such as PC/ABS to balance weather resistance and impact resistance.

4. Motor and Electronic Control System

Application Components:

Motor end cover/housing.

✅Sensor brackets, insulating sheets, etc. for inverters/DC-DC converters.

Request: Translate the above content into English and output the translation directly without any explanation.High temperature resistance, flame retardant, low warpage.

5. High Voltage Distribution Unit

✅Application Components:Various insulating components, brackets, and enclosures inside the PDU are responsible for distributing high voltage electricity to various electrical appliances.

Advantages:

✅Comprehensive performance is balanced and outstanding.Achieved one of the optimal balances among mechanical strength, heat resistance, flame retardancy, and electrical insulation.

Cost-effective:Compared to higher-performance engineering plastics such as PPS and PPA, it has a cost advantage.

✅ Processing Mature:The injection molding process is mature, with good fluidity, making it easy to form complex parts.

✅Low material density:Contributes to the lightweight design of electric vehicles.

Challenges and Responses:

Moisture absorption:PA6's inherent drawback is moisture absorption, which can lead to a decline in mechanical and electrical insulation properties.

Respond to:When designing parts, moisture-proof sealing must be considered; after production, strict drying treatment is required; in long-term high-humidity environments, consider upgrading to materials with lower hygroscopicity.PA66 PPA。

Long-term thermal aging performance:The long-term thermal aging performance above 150℃ is inferior to that of special engineering plastics such as PPS and PPA.

→Response:For extreme high-temperature areas around the motor, materials such as PPS will be selected. Flame-retardant reinforced PA6 is mainly used in "hot areas" but not in "hot spots."

Water resistance.Under high temperature and high humidity conditions, performance may degrade.

→Response: Translate the above content into English and output the translation directly, without any explanation.Improvement can be achieved through material modification (such as adding hydrolysis stabilizers). For harsh environments, PPA still needs to be considered.

1. Halogen-free and environmentally friendly:Global environmental regulations are becoming stricter, and halogen-free flame retardant PA6 has become the absolute mainstream.

Higher heat resistance requirements:With the widespread adoption of 800V high-voltage platforms and the improvement in battery energy density, the requirements for materials' long-term temperature resistance level (such as increasing from 130℃ to 150℃ or even higher) and CTI value are becoming more stringent.

3. Diversification of material systems:At the top of the pyramid, where performance requirements are extremely high,PPA, PPSThe usage is increasing; while in some non-core structural components,Flame-retardant PBT, flame-retardant PPIt is also capturing the market with advantages in cost and hydrolysis resistance. The flame-retardant PA6 is in a key position of "linking the past and the future."

Enhanced flame-retardant PA6 is currently the "main force" and "cost-performance king" in the field of high-voltage components for electric vehicles.It successfully combines high strength, high heat resistance, high flame retardancy, and high insulation properties, perfectly meeting the technical requirements for high voltage in electric vehicles. It is widely used in key components such as high-voltage connectors, internal structural parts of battery packs, and charging systems. Despite facing challenges related to moisture absorption and long-term temperature resistance, through reasonable part design, process control, and material modification, it remains one of the most mainstream and reliable choices available.