Insert the welding needle (usually made of copper or alloy) into the middle hole of the rolled battery cells.

The specifications of commonly used welding needles are Φ2.5*1.6mm,It is qualified to reach welding strength of anode electrode tab ≥12N, low strength can lead to the unstable welding and larger internal resistance. If the welding strength is too high, it is easy to destroy the nickel layer on the surface of the steel shell, leading to hidden dangers such as rust and dew at the welding joint.  TOB New Energy can provide the pneumatic spot welding machine is mainly used for 18650 cylinder call pack welding, it can weld Nickel tab thickness from 0.02-0.2 mm with good welding effect.

The purpose of rolling groove is to fix the battery cells in the stainless steel case. In this process, special attention should be paid to the matching of transverse extrusion speed and longitudinal pressing speed, so as to avoid cutting the shell if the transverse speed is too high, and the nickel layer of the notch falls off if the longitudinal speed is too fast or the groove height is affected to affect the sealing. It is necessary to check whether the process values of groove depth, flaring and groove height reach the standard (through practical and theoretical calculation). Common roller cutter specifications are 1.0, 1.2, 1.5mm. After the completion of the groove, the whole needs to be vacuumed again to avoid metal debris.

The vacuum degree is less than -0.065MPa and the vacuuming time is 1 ~ 2S. The workshop ambient temperature ≤23℃, dew point ≤-40℃.