With the year-by-year development of the new energy vehicle industry, the production and sales of electric vehicles have grown explosively, and the demand for high-performance motors is also increasing. Flat wire windings have achieved rapid development due to their unique advantages compared with round wire windings. The hot direction of new energy vehicle motor research and development.

Flat wire motor introduction

Compared with the traditional round wire winding motor, the flat wire winding motor changes the winding from the round wire to a thicker rectangular wire, which is directly inserted into the stator slot from the end face of the stator. Since it is not affected by the slot size of the stator, the slot fill rate of the flat wire winding can be designed higher, and at the same time, the end size of the stator winding is shorter, and the motor volume can be designed smaller, which makes the motor power density higher, thus achieving The purpose of improving motor efficiency.

Flat wire winding motors have :

• Torque density is about 10%-15% higher than similar competitors
• The motor efficiency is about 0.5%-1% higher than similar competing products
• 15-20% reduction in size
• Rectangular winding, good heat dissipation and reduced copper loss
• High slot full rate
• Flat wire with good stiffness and low running noise

A typical Hairpin stator structure is shown in the figure, mainly including stator core, insulating paper and formed hairpin wire

Laser Technology Application Solutions

Prepare Hairpin wire→Laser paint stripping→Hairpin bending forming → Core inserting insulating paper → Inserting wire → Pressing Hairpin→Outlet end expansion and twisting →Outlet end cutting flat→Laser welding→Electrical performance testing→Stator paint dripping→ Coating → offline

Flat wire motor copper wire paint stripping equipment

The fiber pulse laser with a wavelength of 1070-1080nm is used for processing. The power of the laser is selected according to the beat of the customer's production line. There are 200W-500W to choose from. This set of mechanisms is convenient for online integration, easy maintenance and adjustment, and simple maintenance .

In the early days , CO2 light source was used for stripping. The surface after CO2 light source stripping is relatively smooth, but the adhesive layer cannot be completely removed, which may cause poor subsequent welding processes. Secondly, due to the large size and short life of this kind of laser, it requires maintenance and is not easy for online integration. , Gradually new technology is replaced.

Process selection :

Single-head paint stripping : cut the copper wire, and use automatic rotation to strip the paint on four sides, often used in project evaluation and proofing

Four-head paint stripping : Using four laser heads to peel off at the same time can achieve better resultsand higher efficiency. With the flat wire automaticforming machine, automatic production can be realized. This solution is used in mass production.

Laser welding- flat copper wire laser welding equipment

• High-speed welding is carried out by laser high-speed galvanometer, whether it is welding flat copper wire of single-layer or multi-layer HairPin motor, the efficiency is greatly improved compared with the original argon arc welding process.
• Rely on vision for precise positioning to ensure accurate welding positions
• Benchmarking foreign competing products, multi-point capture, wider field of view, faster efficiency, higher yield rate, continuous optimization and upgrading
• 48 slots, 192 points on 8 layers, photographing and welding time ≤ 60 seconds
• The jig should ensure that the gap and misalignment of the product are within a reasonable range
• The custom-developed welding special software can judge whether the splicing gap meets the welding standard to prevent the entire product from being scrapped.
• High visual recognition rate, greatly improving the yield rate, reducing the situation of missing soldering and repairing soldering

Options available :

Using 6000 watts + galvanometer vision

Annular spot 4000W/2000W + galvanometer vision

HairPin laser welding key points:

1. The card-issuing terminals must be neat and consistent, and the splicing should be tight;
2. Use a special fixture to position the card ;
3. Customized high-efficiency intelligent vision system to ensure stable batch production

Motor Stator - Laser Welding Solution

Motor core welding production line