Laser welding indeed plays a critical role in the application of the new energy industry. It provides high precision, efficiency, and reliability in welding solutions, driving the development and innovation within the industry.
In the manufacturing of solar panels, laser welding equipment is commonly used to connect the wires between solar cells, ensuring efficient and reliable current conduction. In the field of electric vehicle battery manufacturing, laser welding is widely applied in the production process of power batteries. It is used to connect the conductive plates between battery cells and battery modules, ensuring efficient energy transmission. It is also utilized for the busbar connections between battery modules and the entire battery pack, providing high-strength connections while reducing resistance, thus enhancing the performance and stability of the battery pack.In hydrogen fuel cell manufacturing, laser welding is used to connect various components within the fuel cell stack, such as the electrolyte membrane and metal layers, ensuring the integrity and gas-tightness of the structure. In the wind power equipment manufacturing sector, laser welding equipment is used to connect components of wind turbine towers, such as the rotor blades and tower segments, ensuring structural strength and stability.Within the production process of power batteries, laser welding is widely employed to connect the conductive plates between battery cells and the busbars between battery modules and the entire battery pack. Laser welding meets the high requirements of power battery production by providing high precision, flexibility, and efficiency in the welding process. It has become a standard equipment in power battery production lines.
Laser welding plays a crucial role in the manufacturing of power batteries. Power batteries are the core components of new energy vehicles, and welding is an important process in their production, from cell manufacturing to PACK assembly. Within the entire power battery industry chain, laser welding is primarily applied in the production of lithium batteries. As a highly precise welding technique, laser welding is flexible, precise, and efficient, meeting the performance requirements of power battery production. Therefore, it has become the preferred method in the manufacturing process of power batteries and is now a standard equipment in power battery production lines.
In particular, the structure of power batteries involves multiple materials such as steel, aluminum, copper, nickel, etc., which may be used for electrodes, wires, or casings. Consequently, welding processes are subject to higher requirements, whether it involves welding between a single material or multiple materials.
Currently, laser welding equipment is mainly used in several aspects within the new energy industry.
These include front-end applications such as explosion-proof valve laser welding, pole laser welding, and connection piece laser welding. In the middle stage, it is used for sealing welding and sealing ring laser welding. In the back-end, it is used for busbar laser welding and detection line laser welding.
- Explosion-proof valve welding
Explosion-proof valves are thin-walled valve bodies on the battery sealing plate. When the internal pressure of the battery exceeds a certain value, the explosion-proof valve body will rupture and release gas, relieving the pressure and preventing battery explosions. The explosion-proof valve has a clever structure and is often firmly welded using laser welding to join two aluminum metal sheets of a specific shape. When the internal pressure of the battery rises to a certain level, the aluminum sheet will rupture at the designed groove position, preventing further expansion of the battery and potential explosions. Therefore, this process has strict requirements for laser welding, including the need for a sealed weld, precise control of heat input, and ensuring that the destructive pressure value of the weld remains stable within a certain range (generally between 0.4-0.7 MPa). Excessive or insufficient pressure can greatly impact the safety of the battery. As a result, explosion-proof valves commonly use overlapping welding. Extensive practice has shown that using a YLS fiber laser or a composite welding laser from YOUMING can achieve high-speed and high-quality welding, ensuring welding stability, efficiency, and yield rates.
- Pole Tab Welding
The pole tabs on the battery cover plate are divided into internal and external connections. The internal connection refers to the welding between the cell tab and the cover plate’s pole tab, while the external connection involves the welding of the battery pole tab to the connecting plate, forming series or parallel circuits and composing the battery module. The pole tabs of the battery, which represent the positive and negative terminals, are typically made of aluminum for the positive tab and copper for the negative tab. The commonly used structure is a rivet-press structure, followed by full welding after riveting, typically in the form of an 8mm diameter circle. When welding, while meeting the design requirements for tension and conductivity, it is preferable to use fiber laser or composite welding laser with good beam quality and uniform energy distribution. Welding with fiber laser or composite welding laser can achieve stable welding of aluminum-aluminum and copper-copper structures of the electrode tabs, reduce spattering, and improve welding quality.
- Interconnect Plate Welding
Interconnect plates and flexible connectors are crucial components that connect the battery cover plate to the cells. They must consider the requirements of current flow, strength, and minimal spattering. Therefore, during the welding process with the cover plate, it is necessary to have sufficient weld width and ensure that no particles fall onto the cells, preventing short circuits in the battery.
- Shell Sealing Welding
The shell of the power battery is typically made of aluminum alloy or stainless steel, with aluminum alloy being the most common choice, although pure aluminum is also used in some cases. Stainless steel is known for its excellent weldability with laser welding, especially 304 stainless steel, which can achieve visually appealing and high-performance weld seams using both pulse and continuous laser welding methods.
- Seal Pin (Electrolyte Injection Port) Welding
As the final step in cell welding, the yield rate of seal pin welding is particularly important. During seal pin welding, the presence of residual electrolyte can lead to defects such as explosions and pinholes. The key to suppressing these defects is to minimize the heat input.
Advantages of laser welding equipment in the new energy industry
- In terms of explosion-proof valve welding, the use of fiber laser in laser welding equipment can effectively improve welding quality and yield. It is equipped with a dedicated welding head, and the spot size can be adjusted to meet different welding process requirements, ensuring welding effectiveness and stability.
- In terms of pole welding, laser welding equipment adopts a fiber + semiconductor hybrid welding process, which effectively suppresses welding spatter and reduces welding spatter points, improving welding quality and ensuring welding yield.
- In CCS nickel plate laser welding, laser welding equipment adopts IPG fiber laser, which has superior stability, penetration, low attenuation, and high energy utilization compared to other brands. It is highly praised by customers for its high welding penetration rate, fast speed, aesthetically pleasing welds, and strong operability.
