As a core component of new energy vehicle charging systems, the bending radius of the charging gun cable directly affects the safety and stability of the charging process, as well as the cable's lifespan. The bending radius refers to the radius of the arc formed by the cable's centerline when bent. An improperly set parameter, especially when the bending radius is too small, can have multi-dimensional negative impacts on the cable's physical structure and electrical performance.
From a physical structural perspective, a charging gun cable contains multiple layers, including a conductor, insulation layer, shielding layer, and sheath. When the bending radius is too small, stress concentration occurs in each layer due to excessive compression or stretching. The conductor, as the carrier of current transmission, may deform its metallic lattice structure under prolonged stress, leading to conductor breakage or increased local resistance. The insulation layer is prone to microcracks under stress, which can become channels for moisture and impurities to enter, accelerating insulation aging and even causing insulation breakdown. Damage to the shielding layer due to bending weakens its shielding effect against electromagnetic interference, affecting the stability of the charging signal. The sheath, as the outer protective layer of the cable, may develop wrinkles or cracks due to excessive bending, reducing its protective capability against internal structures.
In terms of electrical performance, an excessively small bending radius directly alters the cable's electrical parameters. Conductor breakage or increased resistance can hinder current transmission during charging, leading to decreased charging efficiency or even charging interruption. Damaged insulation can cause leakage, increasing the risk of electric shock, especially in humid environments where leakage current may form a circuit through the human body or equipment casing, endangering personal safety. Shielding failure can increase the coupling between the charging system and the external electromagnetic environment, potentially causing electromagnetic interference, affecting communication between the charging station and the vehicle, and even leading to charging protocol parsing errors, triggering system protection mechanisms to stop charging.
Within long-term use, an excessively small bending radius also accelerates the cable's aging process. The additional heat generated by increased conductor resistance accelerates the aging of the insulation material, making it brittle and cracked, further weakening its insulation performance. Cracked sheaths expose the cable to environmental factors such as ultraviolet radiation and ozone, accelerating the aging of the sheath material and reducing its wear and corrosion resistance. These aging phenomena create a vicious cycle, leading to a continuous decline in cable performance, ultimately shortening its lifespan and increasing replacement costs.
Environmental factors further amplify the impact of an excessively small bending radius. In low-temperature environments, cable materials become less flexible and more brittle. If the bending radius is too small, the cable is more prone to breakage due to stress concentration. For example, in northern winters, if a charging gun cable is exposed to low temperatures for an extended period while bent, its sheath may crack due to embrittlement, and the conductor may break due to low-temperature contraction. In high-temperature environments, the heat generated by increased conductor resistance combined with localized overheating caused by bending can lead to cable overheating failures or even fires.
In practical applications, an excessively small bending radius can also create operational safety hazards. For example, if a user forcibly bends the cable due to space constraints during charging, the connection between the cable and the charging gun may loosen, causing poor contact or arcing, endangering personal safety. Furthermore, excessively bent cables are prone to forming dead bends during storage, which can lead to permanent deformation of the cable over time, making it impossible to return to its original state and further affecting subsequent use.
To avoid these problems, the design and use of charging gun cables must strictly adhere to bending radius specifications. During the design phase, the minimum bending radius should be reasonably determined based on factors such as the cable's outer diameter, conductor material, and insulation material to ensure uniform stress on each layer of the cable structure during bending. During use, users should avoid forcibly bending the cable, especially in low-temperature environments where the bending radius should be appropriately increased; when storing, a natural coiling method should be used to avoid creating sharp bends. When installing charging facilities, the cable routing should be planned reasonably, reserving sufficient bending space to ensure the cable can be arranged with a suitable bending radius.
