Resistance Welding in EV Motors: The Hidden Technology Driving Efficiency
In the motor manufacturing sector, Resistance Welding (RW) technologies—including spot welding, seam welding, and projection welding—are widely used to meet strict high-strength and high-precision requirements for welded components. RW’s inherent advantages of high automation, fast cycle times, energy efficiency, minimal distortion, and ease of operation, align well with the production demands of the motor industry. This technique is commonly applied in critical assembly processes for motor rotors, drive motor assemblies, motor stators, and new energy motor systems. The resultant weld quality directly affects electrical conductivity, mechanical integrity, and long-term reliability, all of which are essential for motor performance and safety.
I. Basic Knowledge of Motors
Automobile motors typically consist of three main components: the stator, rotor, and housing, with the stator and rotor being the focal points of motor technology. Structurally, traditional motor designs adhere to fundamental electromagnetic principles: the stator assembly (stationary coil windings) and the rotor assembly (equipped with permanent magnets or electromagnets) form the dual core of the power source. When current flows through the stator windings, the instantly generated rotating magnetic field acts as an invisible "magnetic driver," precisely propelling the rotor in circular motion. This converts electrical energy into mechanical kinetic energy to drive the vehicle forward, achieving an optimal balance between energy efficiency and power performance. Clearly, the stator assembly's welding wire plays an indispensable role in the overall motor manufacturing process.
Motors are categorized into DC (Direct Current) motors and AC (Alternating Current) motors. Typically, electric vehicles use AC motors, while battery-powered vehicles utilize DC motors. AC motors can be further classified into synchronous and asynchronous types, based on the relative speed between the rotor and the stator.
Generally, motors for electric vehicles must meet the following requirements:
1. The motor should deliver high instantaneous power and power density.
2. For extended range, the motor must maintain high efficiency.
3. The motor should achieve high overall efficiency across both high and low speeds.
4. The motor must have strong overload capacity and provide high torque output.
5. The motor should maintain high torque across a broad speed range.
6. The motor should be durable, reliable, and resistant to dust and water ingress.
7. The motor should be cost-effective to manufacture.
II. Applications of Resistance Welding in EV Motors
Resistance welding application scenarios:
Small motors: In small motors, such as micro motors and small to medium-sized asynchronous motors, the stator core is typically thinner, and the wire diameter of the three-phase winding is relatively small. Resistance welding meets their welding requirements while achieving higher production efficiency.
Mass production: For high-volume motor production, the high automation level and rapid welding speed of resistance welding significantly enhance production efficiency, reduce costs, and ensure consistent weld quality.
Applications of Resistance Welding:
(1) Stator Winding Welding
The stator of a new energy vehicle motor consists of enameled wire windings, and the connection between the ends and the copper terminals is a critical process. Traditional welding requires removing the insulation layer of the enameled wire and using solder. However, resistance welding technology instantly melts the metal through high current, achieving a secure connection without paint removal. For example, a stator welding machine using resistance welding can fuse the enameled wire to the copper terminal, forming a low-resistance, high-tensile joint with minimal indentation and high consistency.
(2) Motor Housing Welding
The motor housing of new energy vehicles is typically made of aluminum alloy or high-strength steel. The low heat-affected zone characteristic of resistance welding reduces material deformation, ensures proper sealing between the heat sink and the housing, and minimizes the risk of thermal failure.
III. Heron Intelligent Equipment: Resistance Welding Equipment Selection
Heron supplies a wide range of medium-frequency DC spot welding and specialized automation equipment for the motor manufacturing industry. These solutions are extensively utilized in the production of automotive starter motors, generators, drive motors, rectifier welding machines, brushes, and other motor components.
(1) 250KVA MFDC Welder For Terminal Block And Enameled Wire
Equipment Advantages:
- Suitable for star-point welding of motors across various specifications
- Equipped with an intelligent control system
- Adjustable workpiece welding height settings
- Compatible with both manual and automated operations
- Adaptable to diverse production environments and process requirements
Equipment Advantages:
Equipment Advantages:
- Suitable for star point/terminal welding of motors across various specifications
- Equipped with an intelligent control system
- Adjustable workpiece welding height settings
- Compatible with both manual and automated equipment
- Z-axis features adjustable stopping height with broad adaptability range
Equipment Advantages:
- Servo pressure control system. During welding operations, the system monitors and controls in real time, automatically adjusting parameters based on the workpiece's actual welding condition. This effectively prevents quality issues such as over-pressure depression and under-pressure cold welding in the weld.
- The high-strength frame design reduces vibration and deformation
- High-precision workpiece positioning provides accurate guidance for welding operations. These features significantly improve welding quality stability and reliability while minimizing defects caused by misalignment.
Resistance welding technology is a core manufacturing process for new energy vehicle motors. Through high-precision control, efficient production, and environmental sustainability, it directly determines motor performance and reliability. Moving forward—from stator winding to lightweight frames, and from battery safety to intelligent control—Guangzhou Heron Intelligent Equipment, as an industry leader in resistance welding, will further advance the development of high-performance new energy vehicles.