EV has been upgraded to a national strategy, with the planned sales reaching 5 million by 2020. With the addition of foreign markets and the construction of charging stations/piles, a large market will be opened up. As the main component of telex, EV cable is the carrier of power signal transmission and plays a huge role. EV cables are mainly divided into charging pile/station cable materials and vehicle high voltage cable materials. Due to the high voltage, high current and harsh operating environment, high safety standards and operational requirements for cable materials are put forward.

　　I. development status and future development direction of EV cable materials

　　•1.1 classification and standards

　　Charging pile/station cable: CQC1103; TUV1908; UL62; EN50620; IEC62821

　　Interior high voltage cable ISO6722 DECRA K175; GB/T12528

　　1.2 CQC/TUV charging wire material requirements and development status

　　Automotive wiring harness manufacturer called material crosslinked elastomers, TPE, TPU, HF - described.properties, PVC (TUV no PVC material), the mainstream of TPE, TPU, require oil resistant tearing resistance weather resistance water resistant to acid and alkali resistance, high and low temperature soft insulation insulation resistance CQC is higher than the TUV, sheath material TPE CQC anti tear for 25, TUV for 15, the current domestic material basic meet the requirements of certification. However, some manufacturers have high hardness, tear resistance NG leads to the risk of cracking, easy to precipitate dust and other shortcomings, in the process of use need to be further adjusted according to the requirements of the customer. Nakasu has addressed these issues.

　　1.3 UL charging wire material requirements and development status

　　According to the UL62 standard of power supply cord, the material should be PVC,TPE, etc., insulation, water and electricity capacity and stability factor requirements, the sheath should be resistant to -40 -- 105°C, ASTM2# oil, UV resistance, 150 ° 2000g thermal deformation, cold and heat impact, vw-1 flame retardant and other tests. • no special environmental protection requirements • currently, most manufacturers use Singapore SPC's nitrile compound elastomer, and domestic manufacturers have also developed it with similar quality.

　　1.4 EN/IEC charging wire material requirements and development status

　　Basic equivalent standard, draft, give priority to with EN50620 commonly used due to GB, IEC standards, IEC generally adopt EN standard, may in the future based on set high standard GB, insulation material performance, use TPE or crosslinked elastomers, sheathed with TPU or crosslinked elastomers, a high degree of resistance to oil demands ASTM2 #, low smoke zero halogen, tearing resistance have requirements, basf, TPU, commonly used currently sheathed insulation is domestic, insulation and sheath material should suit our company has a good development, is currently in the domestic leading. Especially TPU sheath, pH and conductivity is OK.

　　1.5 high voltage wire material requirements and development status

　　ISO6722 commonly used standard, as well as vendors using locomotive lines described.properties of standard GB/T12528, we believe that the 12528 material because it is difficult to achieve soft at the same time, tearing crack resistance, oil resistance, high insulation resistance, high tension line, the material is not suitable for to do EV described.properties meet the material of TPE 6722 or material, the difficulty is 125 degrees heat resistant grades, gasoline resistance, tear resistance, resistance to eager, soft index such as implementation, at the same time we meet 6722 materials are the masses of customers to use, more mature.

　　Ii. Problems in EV cable material development

　　Due to the high voltage system used in EV, high requirements for cable materials are put forward. Improper selection can cause serious consequences

　　Due to the limited internal space of EV, the bending radius of cables is small, and the high current and voltage lead to a large temperature rise

　　The current flame retardant TPE materials generally contain polyphenylene ether, which has poor stress cracking resistance and gap growth resistance. If the wire material is not resistant to cracking, it will cause short circuit of the wire and lead to battery fire and trolley burn.

　　2.2 no oil resistant

　　Since many new energy vehicles are hybrid, and most charging stations are built beside gas stations, they are resistant to gasoline for high-voltage wire and cable materials of charging stations.

　　Diesel oil requirements. If the material is not oil resistant, there will be a risk of failure after oil pollution in future use.

　　2.3 don't wear

　　2.4 non-rolling resistance

　　2.5 high hardness is not easy for construction

　　2.6 precipitation spray

　　2.7 wire belly bulge

　　2.8 poor electrical performance

　　2.9 poor flame retardant

　　2.10 resistance to hot pass

　　2.11 poor water and weather resistance

　　2.12 high temperature resistance

　　2.13 cryogenic hardening

　　Third, the corresponding solution to the problem

　　Cracking resistance • causes:

　　1. The tear strength is too low, which is easy to cause longitudinal cracking of cables under stress and heat

　　Solution: increase tear strength to more than 15KN/M

　　2. High temperature cracking and thermal shock NG heat transfer NG aging NG, etc

　　Solution: through the coordination of antioxidant, the choice of base material to improve the heat resistance of the material

　　3. Low temperature cracking and cold bending, cold impact NG•

　　Solution: improve cold resistance, increase cold resistance

　　4. Cracking in case of chemicals or oil stains

　　Solution: improve the oil and acid and alkali corrosion resistance of materials

　　5. Weather resistance, ozone cracking, etc

　　Solution: choose anti-uv anti-ozone materials from the structure, additives, TPE formula must be adjusted!

　　6. Flame retardant NG adopts efficient flame retardant system, such as ADP+ carbon resin CR1800, etc. Oil resistant NG

　　• solutions:

　　1. The base material is oil-resistant rubber, such as hydrogenated nitrile rubber, acrylic rubber

　　2. Adopt high crystalline material, adjust the balance of soft hardness and oil resistance through IPN structure

　　3. Make the material micro-crosslink and improve oil resistance

　　7. Precipitation spray •

　　The flame retardant which is not easy to hydrolyze and precipitate is selected

　　8. Drum belly

　　Improve the hardness and elasticity of the material, use extrusion die to enrich the outer cover and core wire

　　9. Water resistance, weather resistance, high and low temperature resistance

　　Automobile wiring harness manufacturers said the use of flame retardant is not easy to hydrolysis, high temperature resistant substrate, add anti - UV agents, cold - resistant agents.

　　Iv. Development direction of EV cable materials

　　1. Environmental protection low smoke halogen free tesla requires halogen free UL62 line

　　2. High voltage wire material with high and low temperature resistance of -55_150°C, fast charging wire material with 125°C

　　3. High temperature resistant XLPE or crosslinked elastomer is used for insulation to increase impact on short circuit temperature

　　4. Soft 65A sheath, 80A large square high voltage wire

　　5. Tear resistance and cracking resistance shall be greater than 40•

　　6. High flame retardant ice60332-3c

　　7. Wear and roll resistant

　　8. Thin wall and high strength to reduce the weight of cable

　　9. Slingshot line to facilitate the placement of charging line

　　10. Luminous cable can be used as a warning at night