The connection cable of capacitor discharge spot welder is used for the secondary connection of the head and welding power source. The secondary current voltage is low and the current is high, and the working voltage is generally below 10V. The commonly used connection cable specification models of the energy storage spot welder are mainly 16 square meters, 25 square meters, 35 square meters, 50 square meters, 70 square meters, 90 square meters, 120 square meters, 150 square meters, etc. The number of square meters and length will affect the output of the welding power source, the shorter and thicker the better. The cable has the following characteristics：
1. Working under low voltage and high current conditions, it is required to have certain long-term low resistance characteristics and oxidation resistance.
2. Working temperature generally does not exceed 65 ℃ , the need for a certain degree of heat dissipation performance.
3. The cable requires softness and good bending performance to avoid adverse effects on the pressure applied to the head.
4. With a certain degree of oxidation and corrosion resistance.
5. Long-term use requires good heat resistance and deformation.
6. Lightweight characteristics are required when welding fine workpieces.