A brief discussion on the driving force of the development of the flat wire motor industry for new energy vehicles

01.

Flat Wire Motor Industry Overview & Development Driving Force

1.1 What is a flat wire motor?

Motors are the power source of various machines and can be divided into drive motors and control motors according to their uses. Drive motors directly convert electrical energy into mechanical energy and are mainly used in power tools, household appliances, and other general small mechanical equipment.

The drive motor and its control system are one of the core components of new energy vehicles (battery, motor, electronic control). Its driving characteristics directly determine the main performance indicators of the vehicle, such as climbing, acceleration, and maximum speed. It is an important component of electric vehicles and directly affects the vehicle's power, economy, and comfort.

Bar-wound motor is usually called flat wire motor in China. Flat wire motor technology refers to the use of flat copper wire windings in motor stators to replace the original round copper wire windings. At the same time, unique stator and rotor structure optimization, cooling solution optimization and control optimization technologies are used according to the special structure of the flat wire windings.

1.2 The development direction of the motor industry is mainly to improve performance, and flat wire products are suitable for many needs

The development direction of the motor industry is to improve power performance, improve heat dissipation performance, and reduce materials and volume, thereby leading the motor industry from round wire to flat wire. The future development direction of flat wire motors also mainly lies in these three points.

Performance improvements:

Market product demand: Miniaturization and high speed will be the main development trends of new energy vehicle motors, and miniaturization will inevitably require a significant increase in motor power density.

Policy needs: The "13th Five-Year Plan" proposes that the peak power density of new energy vehicle drive motors should reach 4kW/kg. Currently, this figure is only 3.2-3.3kW/kg.

Technical status: The slot fill rate of a general round wire motor is about 50%, while the slot fill rate of a flat wire motor can reach more than 70%. The increase in slot fill rate means that more copper wire can be filled in the stator slot under the condition that the space remains unchanged, and a stronger magnetic field is generated through a larger current , thereby increasing the power density.

The increase in power leads to a higher demand for improved cooling performance:

Flat wires naturally have better heat dissipation performance: the cross-section of flat wires is rectangular, and the rectangular conductor makes the internal gap smaller, the contact area between conductors and conductors, and between conductors and core slots is larger, and the thermal conductivity of metal is much greater than that of air, so the heat conduction and heat dissipation performance are better. Oil spray cooling technology plays a better role in flat wire design, and the heat conduction effect is better.

Since the gap between the conductors at the winding ends of the flat wire is larger, the cooling oil can directly penetrate into the winding ends, taking away the heat of each conductor and reducing the winding temperature by more than 68%.

After the round wire winding is dipped in paint, the end forms a solid whole, and the cooling oil is difficult to penetrate into the interior. It can only take away the heat of the middle layer conductor, which is easy to form a thermal island inside the winding and affect the heat dissipation performance.

Volumetric material cost reduction:

The flat wire motor has short ends, which saves copper and reduces costs, reduces resistance and improves efficiency.

Due to process problems, the ends of round wires are left very long to prevent damage to the copper wires during the manufacturing process; the ends of flat wire motor windings are wound into special shapes, such as wavy, triangular, stepped, etc. At the same time, flat wires are harder than round wires, so the end size can be reduced by 20% during processing, which saves copper materials and reduces resistance to improve efficiency.

The losses of the motor itself are iron loss and copper loss. Copper loss is the largest source of motor loss, and copper loss can be reduced by changing the cross-section of the wire.

1.3 Based on the current sales trend of new energy vehicles, it is estimated that the global market space for flat wire motors for new energy vehicles will be approximately RMB 61 billion in 2025.

Although the price of a single motor has slowly increased as motor performance has improved, the main growth point of the market lies in volume: increased flat wire penetration and increased dual-motor loading rates.

Flat wire motor penetration rate increased:

Low copper loss, high density, high performance, suitable for high voltage platform, flat wire motor is the future development direction of motor.

Higher slot fill rate: same power, smaller volume, less material and lower cost.

Dual motor loading rate increased - average single vehicle motor demand increased:

The advantages of a single motor are range and cost, and it is widely used in the popularization stage of new energy vehicles; while the advantages of dual motors are high efficiency, flexibility, and safety. In the long run, it is one of the development directions of drive motors for new energy vehicles in the future.

The penetration rate of dual motors in new energy vehicles has increased significantly. Low-end new energy vehicles below 200,000 yuan are still mainly single-motor, but mid-to-high-end new energy vehicles above 200,000 yuan will basically provide high-end dual motor options.

New energy flat wire motor supporting situation

1.4 Industry Chain Analysis

The supply in the upstream of the flat wire motor industry chain is tight, with raw materials, production equipment and production capacity all in short supply.

The demands of downstream customers are clear. Although the OEMs all have their own research and development teams, there are more opportunities for external production suppliers because the related manufacturing costs are clear and the gross profit margins are relatively low.

Midstream and upstream raw materials and production equipment are the main components of costs.

● Rare earth permanent magnet materials account for a high proportion (1/3), and some manufacturers adopt floating pricing to transfer costs.

● Head flat wire motor manufacturers are developing rare earth-free motors to reduce costs, but they will not be available for two years.

● Copper wire & insulation layer technology is difficult, and listed companies dominate.

● Equipment manufacturers can directly produce for tier -1 and OEMs with design capabilities .

The gross profit margin on the downstream application side is low, so there are more opportunities for external suppliers.

● Motor companies mainly supply to tier-1 companies such as OEM group subsidiaries, and a small number of them have the ability to directly contact OEM customers.

● The product gross profit margin is about 15%, and the investment in production lines is large. The common business model is for the group's subsidiaries to do research and development, and purchase core components from external suppliers/select production lines for OEM/integrate external suppliers.

● Only a very small number of vehicle manufacturers choose to produce and use their own products.

02.

Battery safety management technology path: passive safety control

2.1 Important upstream raw materials of flat wire motors: rare earth materials & flat wires

NdFeB material is the permanent magnet material with the best comprehensive performance today. Although its price accounts for a high proportion and fluctuates greatly, China's production is huge and it has both high-end and low-end layouts. Therefore, although a large number of international companies have begun to try rare earth-free motors, there is not much demand for Chinese companies for the time being.

Compared with traditional round wire, the copper wire material used in flat wire motors has significantly higher requirements for elasticity and quality, but the coating step is often completed uniformly by flat wire motor manufacturers. Therefore, the innovation of the copper wire itself is limited, and the main focus is on improving quality and material.

2.1.1 Rare earth materials

Insulation between cells, modules, and systems complement each other and contribute to battery safety. The basic insulation strategy is to use insulation materials with low thermal conductivity and high chemical stability to prevent heat from spreading between modules. Currently, commonly used fireproof insulation materials include aerogel, mica, fireproof coatings, thermal ceramics, etc. From the perspective of application scenarios, insulation materials such as aerogel and intermediate composite panels are generally used between cells, fireproof cotton is generally used between modules, and fireproof blankets are generally used for system insulation.

Market structure:

From upstream rare earth mines to downstream NdFeB, China currently occupies an absolute dominant position in every production link. Among them, the output of rare earth mines accounts for about 60%, while the rare earth smelting and separation, rare earth metal smelting, and NdFeB manufacturing links account for about 90%. Even for high-performance NdFeB, China's output has reached 70%+. At present, my country has basically achieved independent control of the NdFeB industry chain.

According to the latest USGS data in 2022 , China's rare earth production accounts for 70%. In 2022, the global rare earth production was about 300,000 tons of REO, and China's production reached 210,000 tons of REO, accounting for 70%, ranking first in the world.