Advanced Electric Motor Winding Technologies: H-pin, X-pin, N-pin, and Mini-pin

The mainstream flat wire winding types currently include Hairpin and I-pin. Among them, Hairpin has a relatively higher adoption rate. Most companies prefer the Hairpin process due to its comparatively lower technical difficulty. On the other hand, I-pin, which requires double-ended welding, is adopted only by a few companies, such as United Automotive Electronic Systems (UAES).

Both Hairpin and I-pin windings require welding at their ends, necessitating the retention of straight segments to facilitate the welding process. Typically, a length of over 8mm is required. Since these straight segments do not contribute to torque generation and are only used for connections, they inherently limit further advancements in the miniaturization of hairpin motors.

In recent years, equipment manufacturers and OEMs have begun exploring ways to reduce the end height of hairpin windings, leading to the emergence of various short-pin designs. Among these, the development of X-pin windings has been particularly prominent. Why is this the case?

This prominence can be attributed to the X-pin winding's innovative structural design, which significantly reduces the end height while maintaining welding quality and motor performance. By minimizing the unused straight segments, X-pin windings address the constraints of traditional designs, enabling better compactness and efficiency. This makes them highly attractive for applications demanding smaller, more efficient motor designs.

Laser Welding Highlights

The reason why the X-pin?motor?is said to be so good by the outside world is that its end height can reach the same end height as wave winding, but its manufacturability can reach the manufacturability of the Hairpin motor, but there will be some differences in the process. After the straight line segment of the X-pin motor is canceled, the requirements for wire twisting are higher. The wire twisting accuracy directly affects the subsequent shaping process. If the wire twisting accuracy is not enough, it will make the shaping difficult; conversely, if the shaping is not in place, it will cause the distance between the wires to be too large, thus affecting the quality of welding.

The reason for retaining the straight segments in the hairpin motor is primarily due to the use of laser welding for winding ends. This method offers the advantage of precise energy control during the welding process, ensuring the quality and reliability of the welds.

However, during the welding process, if there is insufficient straight segment length, the high-temperature laser can damage the nearby enameled wires, compromising their insulation layer. This can lead to a decline in the motor's electrical performance and increase the risk of short circuits or other failures.

Therefore, when designing the windings of hairpin motors, it is essential to account for this factor and reserve sufficient straight segments to ensure safe and reliable welding operations. The recent ability to eliminate these straight segments is primarily attributed to advancements in laser welding technology, which have enhanced precision and minimized the risk of damage to adjacent enameled wires.

HONEST Automation independently developed an innovative X-pin stator with high-efficiency and stable welding technology that adopts a flexible laser welding architecture. Low welding temperatures, excellent wettability, superior conductivity, and high welding strength characterize this approach. Additionally, the process ensures that the enamel coating remains undamaged after welding, fully meeting the requirements of X-pin motor applications. Furthermore, the investment cost for this technology is significantly lower than that of Hairpin welding.

Performance Optimization and Cost Breakthrough

Currently, it isn't easy to systematically quantify how much the X-pin technology can reduce the end height, as it varies across different manufacturers. However, the typical reduction range is approximately 6–10mm. Some companies have also adopted alternative methods to lower the end height of windings.?

The N-pin technology, introduced by SHedrive, represents an intermediate solution between Hairpin and X-pin in terms of end height. Its main innovation lies in the use of a low-heat welding process, which minimizes winding height while ensuring the enamel coating remains intact. Compared to X-pin production lines, N-pin lines have lower investment costs, superior feasibility, and greater reliability. Crucially, the cost of retrofitting existing Hairpin production lines for N-pin technology is significantly lower, resulting in more stable production quality.

In terms of manufacturing, the mass production process for the N-pin is highly compatible with that of the hairpin motor. This compatibility allows existing hairpin motor production lines to be easily converted to N-pin production line, enabling rapid product transitions and production adjustments.

From a product perspective, the N-pin stator achieves its design by fine-tuning the straight segment at the welding end. It retains a portion of the necessary length to leverage critical processes from Hairpin stators, such as twisting, weld point clamping, and welding. This approach not only reduces the R&D and production investment for N-pin stators but also improves the yield rate. Through this innovative process design, the N-pin stator maintains high performance while optimizing cost-effectiveness and production efficiency.

HONEST Automation has developed advanced production line equipment for X-pin and Mini-pin motors, offering significant advantages over traditional Hair-pin motor equipment. These innovations greatly reduce copper wire material costs and save space, resulting in enhanced energy density and improved motor performance. Additionally, HONEST's latest non-cutting hairpin twisting machine?solution is fully compatible with Mini-pin, X-pin, and Hair-pin motors.

If you’re looking for assembly equipment, welding solutions, or twisting wire machines tailored to these motor types, we’re here to help. Simply leave us a message online, and our motor equipment experts will provide you with personalized solutions and professional advice to meet your specific needs.