Introduction to the standards for high-voltage system connection cables for electric vehicles

In the high-voltage system of electric vehicles, the connection cables are key components, and their standards are crucial to the safety and performance of the vehicle. At present, a series of standards have been formulated for high-voltage connection cables for electric vehicles at home and abroad. These standards cover electrical safety, mechanical properties, environmental adaptability and other aspects.

From the perspective of electrical safety, GB/T 37133-2025 clearly stipulates many key indicators of high-voltage connection cables. In terms of insulation resistance, it is required that the insulation resistance between high-voltage conductors and high-voltage conductors, between high-voltage conductors and interlocking conductors, and between high-voltage conductors and shells should be greater than 100MΩ for 60 seconds under a test voltage of 1000V; between high-voltage interlocking conductors and shells, between high-voltage interlocking conductors and shielding layers, and between shells and shielding layers, the insulation resistance should also be greater than 100MΩ for 60 seconds under a test voltage of 500V. The withstand voltage requirements are also very strict. Basic insulation must withstand an AC voltage of 2U + 1000V (rms) for 60 seconds, and double insulation must withstand an AC voltage of 2U + 3250V (rms) for 60 seconds (U is the maximum working voltage. If DC voltage is used instead of AC voltage, it must be multiplied by 1.41 times).

In terms of mechanical performance standards, cables must have certain tensile strength and bending properties. For example, in actual use, it is necessary to avoid cable breakage or damage due to vibration and bumps during vehicle driving. It is generally stipulated that under specific tensile test conditions, the cable should not break or other abnormal conditions; for bending performance, it is required that the electrical performance of the cable can remain stable under a certain bending radius and number of bends.

Environmental adaptability standards are also indispensable. Electric vehicles may face various complex environmental conditions, such as high temperature, low temperature, humidity, salt spray, etc. Taking temperature as an example, the cable needs to work for a long time without performance degradation in a specified high temperature environment (such as 125℃ or even higher); in a low temperature environment (such as -40℃), it can still maintain good flexibility to ensure normal electrical connection. In the salt spray resistance test, it must be carried out in accordance with the provisions of GB/T 2423.17. The high-voltage wire harness should be in a normal installation state in the test box. The test time is 16h. After the test, the high-voltage wire harness should be able to work normally after being powered on after (1-2)h of static recovery.

In terms of appearance, in order to play a high-voltage warning role, high-voltage connection cables are usually required to use orange outer skin, and the surface should be free of burrs, flash and similar sharp edges, and there should be no defects such as damage and deformation.

The formulation and implementation of these standards provide a clear basis for the design, production and testing of high-voltage connection cables for electric vehicles, which helps to ensure the stable operation of the high-voltage system of electric vehicles, improve the overall safety and reliability of electric vehicles, and promote the healthy development of the electric vehicle industry.

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