Flat Wire Motors Are Highly Favored in This Field

                                                             Flat wire motors are highly favored in this field

 Compared with other equipment, new energy vehicles have more stringent requirements for the power density of supporting motors, because the power density of the motor directly affects the physical layout of the parts and the endurance effect of the car. The 13th Five-Year Plan proposes that the peak power density of new energy vehicle drive motors should reach 4 kilowatts per kilogram (currently 3.2-3.3 kilowatts per kilogram); Miniaturization and high speed will be the main development trend of new energy vehicle motors, and miniaturization will inevitably require a significant increase in motor power density.

 1st generation flat wire motor, using axial plug hairpin winding technology. That is to say, single-issue card winding, this winding makes the slot arrangement unconventional, thereby greatly improving the slot full rate, and the end fine type is enhanced, the final effect of these two improvements is to reduce the flow resistance of the winding by 30~40%.

 Although the card generator can reduce the DC resistance, when running at a high frequency, a high-frequency eddy current electric field will be induced on the winding, resulting in a skin effect. From this point of view, flat wire motors are more suitable for medium and low speed applications. In view of the shortcomings or defects of this type of motor, the second and third generations were subsequently improved and developed.

 From the analysis of heat dissipation and power density improvement, the end of the round wire winding becomes a solid whole after being impregnated, and it is difficult for the cooling oil to penetrate into the interior, which cannot take away the heat generated by the middle layer conductor, and it is easy to form a thermal island inside the winding. The end oil injection cooling technology is used in the flat wire motor, because there is a large gap between the end conductors of the flat wire, and after the oil is discharged from the nozzle, it directly penetrates into the end of the flat wire winding, taking away almost the heat of each conductor. The combination of flat wire and end oil cooling technology greatly improves the heat dissipation capacity of the winding, and finally improves the power density of the whole machine.

 In summary, the advantage of flat wire motor is high slot full rate, the traditional motor winding slot full rate is about 45%, and the hairpin winding can reach about 70%: the flat wire winding has good heat dissipation, the contact area between the windings is large, the gap is small, the end is short, and the volume is small. However, due to the thick winding wire, the high-frequency skin effect is obvious, and the copper consumption increases: the requirements for copper wire are higher, after the coil is formed and bent, the insulation layer is easily damaged, compared with the round wire winding, the flat wire winding processing technology is complex, and the production equipment.