Secondary battery

The slurry-coated coated foil passes through the drying facility while maintaining an appropriate tension to prevent drying. In the case of a convection dryer, the intensive travels at a speed of 35 to 80 meters per minute over a long path of up to 100 meters. As slurry moisture is slowly removed at a high temperature of 160 °C, active moisture settles on the surface, and a significant amount of energy is concentrated during this process. Laser drying systems with BEAM SHAPING technology can not only reduce the size of the facility to 10 meters, but also reduce energy consumption by up to 50%.

Notching is a process of molding a “tap (-: Anode, +: Cathode)” on the metal foil of an electrode that has been slitting. While the electrodes wound on the roll-to-roll equipment are continuously loosened, the laser shapes the notch at high speed according to the customer's desired design.

A battery tab is a positive and negative connector that transfers the cell's current to the outside. Since the cell tab is connected to the module bus bar and the module consists of a pack, lasers are an optimal solution for performing thousands of welds from individual cells to the final terminal.

In the case of a rectangular battery, it has a relatively stable structure for internal gas pressure. Since there are no restrictions on the choice of anode, cathode, and electrolyte materials, they have the advantage of greater room for energy density improvement and can be more easily combined into battery modules compared to cylindrical ones.

Terminal welding after insertion of JELLY ROLL and sealing after FIXTE filling are performed. Cylindrical cells have very thin sheets, so if the depth is not precisely controlled, the material as well as the inside of the cell will be damaged. The keyhole created by the fiber laser's fine spot can perform the liquefaction and cooling process of the metal very quickly while minimizing unnecessary deformation.

The POUCH CELL is relatively lightweight and flexible because it does not use metal enclosures, and boasts a packaging efficiency of 90 to 90%. A laser system equipped with SMART FOCUSING and VISION is required to maximize volume without affecting the lamination structure of the anode and cathode due to pouch sealing.

In order for multiple cells to be combined into a battery module, highly conductive bus bars such as aluminum and copper must connect the cells into a single assembly. Although the initial cost is high compared to other methods, lasers are superior in energy efficiency and low maintenance costs. In particular, since consistent quality work is performed at a high speed, it shows excellent productivity for connecting bus bars and terminals, which increase exponentially with the size of the module.

Visual inspection of welds and image matching inspections have limitations in determining process defects. An electrical ohmmeter can also be used as a non-destructive test, but the measurement takes a long time and the high voltage in the battery pack also damages the device. K2 implements proactive quality control by applying SEAM TRACKING and OCT to measure melt depth at the same time as laser welding.