The structure of a photovoltaic cable mainly consists of a conductor, an insulation layer, a sheath, and optional special functional layers. The conductor typically uses high-purity electrical copper or tinned copper stranded wire. The insulation layer, wrapping around the conductor, primarily serves an electrical insulation function; common materials include cross-linked polyethylene (XLPE), polyethylene (PE), fluoroplastics, low-smoke halogen-free polyolefins, and irradiated cross-linked polyolefins. Some high-performance insulation materials, such as high-temperature resistant halogen-free flame-retardant cross-linked polyolefin insulation materials, are composed of ethylene-vinyl acetate copolymers and linear low-density polyethylene.
The sheath, as the outermost protective structure of the cable, needs to provide mechanical protection and environmental resistance. Common materials include polyvinyl chloride (PVC), polyurethane (PUR), halogen-free flame-retardant materials, and modified polyvinyl chloride. In addition, there are specially developed long-life photovoltaic cable sheath materials resistant to ultraviolet aging, whose components include high-density polyethylene, benzotriazole ultraviolet absorbers, and hindered amine light stabilizers to enhance weather resistance.
To adapt to complex application environments, photovoltaic cables may incorporate various special designs, such as anti-aging layers and UV-absorbing layers in the insulation and sheath; armor layers to form a physical barrier against rodents and termites; independent air-filled cavities as waterproof layers; and double-layer co-extrusion structures consisting of inner and outer cable materials. Additionally, designs may include adding vegetable oil-based plasticizers to improve cold resistance or using nano-coating technology to treat the sheath and enhance UV resistance.