Two key points of energy vehicles: power battery and lightweight

At present, the early stage of the reform of the automobile industry is mainly electrification.

During this period, the core components of the car are no longer the “three big parts” (engine, gearbox and chassis), but the three-electric system (battery, motor and electronic control), accounting for more than 50% of the cost of new energy vehicles. Among them, the cost of power battery accounts for 90% of the cost of three electric power. Therefore, the power battery system can be called the “heart” of new energy vehicles.
The lightweight of new energy vehicles is mainly materials related to electronics, such as connectors, charging interfaces, and peripheral materials for power batteries. Replacing metal with plastic can reduce weight by about 30% when the performance meets the requirements. At present, a pure electric vehicle can reduce weight by about 100KG by using lightweight plastics. ‍

Engineering plastics for new energy vehicles, combined with the usage scenarios of automotive products, need to meet the following performance requirements:

Chemical corrosion resistance, oil resistance, high and low temperature resistance;
Excellent mechanical properties, high fluidity, excellent processing performance;
Excellent surface properties and good dimensional stability;
It has good waterproof, moisture-proof, flame-retardant, environmental protection and other properties and thermal conductivity;
Good anti-dielectric performance, suitable for electrical places;
Good weather resistance, good long-term performance, can be used in harsh environments for a long time. ‍

1. Power battery system
Power battery bracket
Power battery brackets require flame retardancy, dimensional stability, chemical resistance, and high strength. Currently, modified PPE, PPS, PC/ABS, etc. are mainly used.

Power battery cover
Power battery cover plates require flame retardancy, dimensional stability, chemical resistance, and high strength. Currently, modified PPS, PA6, and PA66 are mainly used.

Power battery box
The power battery box requires flame retardancy, dimensional stability, chemical resistance, and high strength. Currently, modified PPS, modified PP, and PPO are mainly used.

DC motor frame
DC motor frame mainly uses modified PBT, PPS, PA.

Relay housing
Modified PBT is mainly used in the casing of automotive electronic control relays.

Connector
New energy vehicle connectors mainly use modified PPS, PBT, PA66, and PA.
2. Motor drive system and cooling system

IGBT module
The IGBT module is the core device of the electric control system and DC charging pile of the new energy vehicle, which determines the energy utilization rate of the vehicle. In addition to the traditional metal and ceramic materials, PPS engineering plastics are gradually applied.

Car water pump
Electronic water pump rotors, water pump casings, impellers, water valves, etc. require high toughness, high wear resistance, and high strength. Currently, modified PPS materials are mainly used.

Three, five major engineering plastics

PA

Polyamide, commonly known as nylon, has many types of PA in industrial use, and the commonly used ones are PA6, PA66 and PA610. Due to the influence of thermal expansion and water absorption, the dimensional stability of the part is poor, and the shrinkage rate is 1-2%. Pay attention to the dimensional change of moisture absorption after molding. The water absorption rate is 100%, and it can absorb 8% when the relative moisture absorption is saturated. The suitable wall thickness is 2-3.5mm.
PA is mainly used in the manufacture of hoses (brake hoses, fuel pipes), combustion oil filters, air filters, oil filters, water pump housings, water pump impellers, fans, brake fluid tanks, power steering fluid tanks in the automotive field , White shutters, headlight housings, seat belts.

PMMA

Polymethacrylate, commonly known as plexiglass, is resistant to outdoor aging and has excellent light transmission. Suitable plastic products: transparent structural parts with certain strength requirements.
Due to its good light transmission performance, PMMA is widely used in automotive lighting signs, door glass and lamp glass cover.

POM

POM, commonly known as plastic steel, shrinkage rate 2-3.5%, suitable wall thickness: 1.5-2.5mm.
POM is used in automobiles to manufacture instrument panel glove box accessories, various valves (drainage valves, air conditioner valves, etc.), various impellers (water pump impellers, heater impellers, oil pump wheels, etc.), various electrical switches and electrical instruments Small gears, various handles and door pins etc.

PC

Polycarbonate has outstanding impact toughness and creep resistance, good heat resistance and cold resistance. The shrinkage rate is 0.5-0.7%, and the suitable wall thickness is 2-3.5mm. Adding glass fiber to PC can improve its shrinkage, mechanical strength and temperature resistance. Long-term use at around 100°C will increase the rigidity, and annealing can be used to improve the internal stress.

PC/ABS

PC/ABS is a blend material ofPCand ABS, which is usually supplied in the form of pellets after blending. If you simply mix the two materials and inject them directly, the effect will be poor and delamination will occur; the advantage of PC is rigid and tough, but the disadvantage is stress cracking and high viscosity; the advantage of ABS is good fluidity, but the surface Low hardness; the blended material PC/ABS retains the advantages of both; PC/ABS has high surface hardness, high rigidity and toughness, and high resistance to stress cracking; its mechanical properties in between.
PC is mainly used in the automotive field to manufacture lampshades, left and right wheel cover guards, instrument bezel body (PC/ABS), left and right air frame covers, middle air frame covers (PC/ABS), and rear bumper cushions.

PU

Polyurethane, according to the different polymerization reaction products, is commonly divided into rigid polyurethane and soft polyurethane.
Polyurethane foam is widely used in automotive interiors and vibration-absorbing parts, such as coating materials, polyurethane rigid plastic sheets, polyurethane elastomers, seat soft foam materials, decorative parts, sofa leather, and roof accessories; the most widely used The most popular are all kinds of soft and hard polyurethane foam materials, which have vibration isolation, sound insulation, noise reduction, thermal insulation; PU can also be made into automotive polyurethane coatings, adhesives, sealants, etc.
PU representative parts on automobiles include dashboards, rearview mirrors, bumpers, seat cushions, headrests, steering wheels, dashboard anti-vibration pads, pillar trims, front roof linings, window frames, roofs and side roofs Frame decoration, door liner, sun visor, rear top shelf decoration, etc.