One is to adjust the effective value of the welding current so that the heat of the internal power source changes significantly; second, due to the concentration and contraction of the contact points of the two weldments during the operation of the automatic spot welding machine, concentrated heating occurs there. And the plastic junction area first seems to be uneven during spot welding. This disadvantageous factor, different welding current waveforms, changing the electrode shape and end face size, etc., can change the shape of the current field, control the current density distribution, and achieve It is formed for the purpose of controlling the shape and position. Plus, the generated resistance heat increases, and the shear strength of spot weld nuggets and joints is improved.

　　However, if the welding current is too large, it will cause the base metal to overheat, and even the loss of the electrode end face will increase. When the 18650 lithium battery is energized when spot welding, the heat generated by the two electrodes is used to heat the welding area to form a welding spot, which is called effective heat. For a certain welding material and a certain welding zone metal volume, it has nothing to do with the length of heating time; the other part is transferred to the electrode, the cold metal around the welding zone and the air during heating, which is called heat loss, as The extension increases over time. If the welding is performed instantaneously, the heat loss will be equal to zero, and the total heat will be equal to the effective heat. Therefore, when the total heat is to be increased, the method of extending the welding time cannot be used.

　　Electrode pressure First of all, the total resistance between the electrode pressures has a significant effect, thereby affecting the welding heat during the spot welding process. Secondly, the electrode pressure has a great influence on the heat dissipation performance of the welded joint. When the electrode pressure is too small, the electricity between the two electrodes will increase the welding heat. At this time, the heat dissipation of the welded joint is poor, and it is easy to cause splashes in the early stage; when the electrode pressure is too high, the resistance between the two electrodes is small, the current density is reduced, the welding heat is insufficient, and the heat dissipation performance of the joint is improved, resulting in nucleation size When the electrode pressure becomes smaller, the penetration rate decreases. When the electrode pressure is strictly selected for welding, the minimum electrode pressure should be selected without spark splash, which can ensure energy saving and welding quality.

　　Welding power source, resistance spot welding equipment usually consists of three main parts: main power source, control device and mechanical device. Among them, the main welding power source is one of the most important parts, and the selection of a controllable welding power source is the key.