Safety issues at EV charging stations

Electric vehicle charging station is a kind of electrical equipment specially used to charge electric vehicles, with the promotion and popularization of electric vehicles, has gradually become a more common electrical product in daily life. Although EV charging stations have multiple safety measures, in-service public EV charging stations are still one of the products with more safety accidents, especially in places with poor electricity environments, electric shock and fire accidents occur from time to time, and in recent years, related injury cases have been reported.
Based on the national standards of electric vehicle charging stations and the standards of the Energy Bureau, this paper discovers the safety problems of in-service public electric vehicle charging stations through on-site inspection, analyzes the on-site safety problems of in-service electric vehicle charging stations, provides theoretical support for the supervision of in-service charging facilities, and provides a theoretical basis for the healthy and long-term development of the charging facility industry.
1. Standard status of electric vehicle charging stations at home and abroad
Foreign electric vehicle charging stations mainly adopt IEC standards, domestic electric vehicle charging station standards on the basis of reference to IEC standards, combined with China's actual situation, including electric vehicle charging station use environment, communication standards, interface standards, etc., add many revisions with Chinese characteristics, such as the communication protocol between electric vehicle charging stations and battery management systems, standards for the interoperability of electric vehicle charging stations, and increase energy industry standards in combination with the actual situation in China. These are not discussed in this article. Table 1 compares national and international standards.
2. Safety status of electric vehicle charging stations
Electric vehicle charging station is a high-current and high-voltage electrical products, mainly distributed in office buildings, large supermarkets, open-air public parking spaces, residential areas aboveground and underground parking spaces and public charging stations and other crowded places, the surrounding environment is complex, once the quality is not up to par, it will cause the risk of electric shock of personnel and the risk of fire in the place.
According to the national standards and energy bureau standards above, the on-site situation of electric vehicle charging stations has found the following common problems.
2.1 Electric shock protection
According to JB/T5777.4-2000, the resistance between any point that should be grounded in DC power equipment and the total ground should not be greater than 0.1Ω, and the contact resistance between the electric vehicle charging station shell and the ground is greater than the standard limit of 0.1Ω, the main reason is that the contact screw is severely rusted or loose, resulting in a large resistance, which in turn affects the electric shock protection ability of the shell, and the human body is easy to cause the risk of electric shock when touching the sample shell.
2.2 Direct contact of live parts
Due to long-term use of the charging gun, or violent use by the owner, the protection of the live parts falls off, and the live parts may ** after contact with sharp objects, causing the risk of electric shock to the user.
2.3 Insulation performance
Since the sample of the electric vehicle charging station belongs to the high-voltage product, if the insulation performance of the electric vehicle charging station is unqualified, it is easy to cause the electric vehicle charging station to be broken down or flashover phenomenon due to static electricity, lightning strike, cross-current and other factors, which will lead to direct contact between the human body and high-voltage live parts, resulting in the risk of electric shock. The phenomenon of unqualified insulation performance is that the insulation resistance of the DC electric vehicle charging station sample is less than 10MΩ under the test voltage of 1000V.