Advantages and types of flat wire motors for new energy vehicles

The main components of the flat wire motor can be separated into stator components, rotor components, end covers and auxiliary standard parts. Among these components, the stator assembly is the key to determining the performance of the motor and consists of the stator core, copper wire windings, lead wires, and insulating materials. Copper wire winding refers to adding an insulating coating to the outside of the copper wire to make an enameled wire, and then connecting it end to end to form a winding. The rotor assembly consists of a rotating shaft, bearings, and a rotor core.

1. Advantages of flat wire motors

During the manufacturing process, the flat wire winding needs to be shaped like a hairpin first, inserted into the stator slot, and then the end of the hairpin is welded at the other end. Compared with round wire motors, flat wire motors can pack more conductors under the same conditions by changing the stator cross section and end structure. The gaps between the conductors are obviously much smaller and more uniform and regular, resulting in flat wires. Advantages of motors over round wire motors.

Current requirements for drive motors in new energy vehicles are mainly reflected in high power density, wide speed range, large starting torque, wide efficiency range, and strong heat dissipation requirements. Thanks to technological breakthroughs, flat wire motors have demonstrated their overwhelming advantages in various dimensions. The performance of existing round wire motors can no longer meet the performance requirements of new energy vehicle drive motors.

As the power demand of electric vehicles increases, the speed of the motor is getting higher and higher, and the frequency of the alternating current passing through the winding is also getting higher and higher. Motors using flat wire winding technology have a larger wire area, so resistance and energy loss are reduced, and motor efficiency is improved.

2. Types of flat wire motor stators

A. I-pin winding

Traditional I-pin route. The biggest feature is the simple manufacturing process. The I-pin winding is an axial embedded winding. After directly inserting the straight flat wire conductor axially into the core slot, the two ends are twisted and welded. The manufacturing process is relatively simple, but due to the welding parts It takes up additional radial dimensions, has a long tail, and consumes a lot of copper. As the temperature increases, the efficiency will also decrease.

B. Hair-pin winding.

Hair-pin winding requires preforming the flat copper wire into a hairpin shape, which is the current mainstream form of flat wire winding. The characteristic is that only one end needs to be welded, the length of the end is shorter, the copper consumption is small, the temperature rise is reduced, and the efficiency is improved. At the same time, the weight and volume of the motor will be smaller. However, the process is complex and requires high equipment and copper wires. The overall copper consumption is lower than that of the I-pin winding, and the motor efficiency is also improved to a certain extent.

In addition to the difficulty of the molding process, the process difficulty of flat wire hairpin windings also lies in the insulation treatment of the winding ends to avoid direct contact between the windings and the stator. At the same time, in order to ensure a compact structure, the gap between the windings must be small enough.

The current mainstream technology route is the Hair-pin route, also known as the hair-pin motor. In the next few years, Hair-pin will remain the mainstream flat wire motor technology, with an estimated proportion of about 80%-90%; new technologies of continuous wave winding and X-pin will account for 10%-20%.

C. Continuous wave winding.

Wave-wound rectangular wire is a winding process with fewer solder joints and high design flexibility. The process steps are greatly simplified compared to Hair-pin, and there is no need to weld the ends after forming. Its biggest advantage is that the space is smaller than Hair-pin, and it is more suitable for the current 800V oil cooling trend. However, its technical requirements and corresponding single-line value will also be higher. It is still in its infancy, and independent research and development is limited to plug-in hybrid models.

D. X-pin winding.

X-pin winding has obvious advantages mainly in slot fill rate, but the technology is also more difficult and is currently in the research and development stage.

3. Hair-pin flat wire motor stator production process

The process flow of stator production is roughly divided into insulating paper insertion-wire forming-wire insertion-flaring-twisting-welding-paint coating. Insufficiency in any link will lead to poor reliability and consistency of the motor and affect the motor. Use performance.

Ningbo Nide Machinery Equipment Co., Ltd., was committing to provide customers with highly automated, intelligent, and flexible production solutions, and focusing on the production line of stator, rotor and final assembly of various motors.

At present, the products cover the professional manufacture of new energy motor stator and rotor, hairpin motor, automatic aluminum casting rotor line, brushless motor/ BLDC motor, universal motor, wheel hub motor, etc., which are used in new energy vehicles, household appliances, industrial motors, water pump motors, servo motors, etc. If you want more details for flat wire motors for new energy vehicles,please contact us feel free.