Standards for high voltage connectors
The standards of high-voltage connectors are currently based on industry standards. In terms of standards, there are safety regulations, performance, and other requirements standards, as well as testing standards.
At present, in terms of the standard content of GB, many areas still need further improvement and improvement. The most mainstream designs of connector manufacturers will refer to the industry standard LV jointly formulated by the four major European OEMs: Audi, BMW, Daimler, and Porsche. series of standards, North America will refer to the industry standard SAE/USCAR series of standards formulated by the wire harness connection organization EWCAP, a joint venture between the three major European OEMs: Chrysler, Ford, and General Motors.
OSCAR
SAE/USCAR-2
SAE/USCAR-37 High Voltage Connector Performance. Supplement to SAE/USCAR-2
DIN EN 1829 High-pressure water spray machinery. Safety requirements.
DIN EN 62271 High-voltage switchgear and controls.Liquid-filled and extruded insulated cables. Liquid-filled and dry cable terminations.
Applications of high voltage connectors
From the perspective of the connector itself, there are many classification types of connectors: for example, there are round, rectangular, etc. in terms of shape, and high frequency and low frequency in terms of frequency. Different industries will also be different.
We can often see a variety of high-voltage connectors on the entire vehicle. According to the different wiring harness connection methods, we divide them into two categories of connections:
1. Fixed type directly connected by bolts
Bolt connection is a connection method that we often see on the entire vehicle. The advantage of this method is its connection reliability. The mechanical force of the bolt can withstand the influence of automotive-level vibration, and its cost is also relatively low. Of course, its inconvenience is that the bolt connection requires a certain amount of operating and installation space. As the area becomes more platform-oriented and the interior space of the car becomes more and more reasonable, it is impossible to leave too much installation space, and from batch operations and It is not suitable from the perspective of after-sales maintenance, and the more bolts there are, the greater the risk of human error, so it also has its certain limitations.
We often see similar products on early Japanese and American hybrid models. Of course, we can still see many similar connections in the three-phase motor lines of some passenger cars and the battery power input and output lines of some commercial vehicles. Such connections generally all need to use external boxes to achieve other functional requirements such as protection, so whether to use this method needs to be based on the design and layout of the power line of the vehicle and combined with after-sales and other requirements.
2. Plug-in connection
In contrast, a mating connector secures the electrical connection by joining two terminal housings to provide a connection to this wiring harness. Because the plug-in connection can be plugged in manually, from a certain perspective, it can still reduce the use of space, especially in some small operating spaces. The plug-in connection has transitioned from the early direct contact of male and female ends to the method of using elastic conductors in the middle to contact materials. The contact method of using elastic conductors in the middle is more suitable for larger current connections. It has better conductive materials and better elastic design structures. It also helps reduce contact resistance, making high-current connections more reliable.
We can call the middle elastic conductor contact. There are many ways of contact in the industry, such as the familiar spring type, crown spring, leaf spring, wire spring, claw spring, etc. Of course, there are also spring-type, MC strap-type ODUs. Line spring type, etc.
We can see the actual plug-in forms. There are also two methods: the circular plug-in method and the chip plug-in method. The round plug-in method is very common in many domestic models. Amphenol 、TE‘s large currents of 8mm and above are also They all adopt a circular form;
The more representative “chip type” is PLK contact like Kostal. Judging from the early development of Japanese and American hybrid models, there are still many applications of chip type. For example, the early Prius and Tssla have more or less All adopted this method, including some parts of the BMW bolt. From the perspective of cost and heat convection, the plate type is indeed better than the traditional round spring type, but I think the method you choose depends on your actual application needs on the one hand, and it also has a lot to do with the design style of each company.
Selection criteria and precautions for automotive high-voltage connectors
(1) The voltage selection must match: the rated voltage of the vehicle after load calculation should be less than or equal to the rated voltage of the connector. If the vehicle’s operating voltage exceeds the rated voltage of the connector and is operated for a long time, the electrical connector will be at risk of leakage and ablation.
(2) Current selection should match: after load calculation, the rated current of the vehicle should be less than or equal to the rated current of the connector. If the vehicle’s operating current exceeds the rated current of the connector, the electrical connector will be overloaded and ablated during long-term operation.
(3) Cable selection requires matching: The matching of vehicle cable selection can be divided into cable current-carrying matching and cable joint sealing matching. As for the current carrying capacity of cables, each OEM has dedicated electrical engineers to carry out matching designs, which will not be explained here.
Matching: The connector and cable seal rely on the elastic compression of the rubber seal to provide contact pressure between the two, thereby achieving reliable protection performance, such as IP67. According to calculations, the realization of the specific contact pressure depends on the specific compression amount of the seal. Accordingly, if reliable protection is required, the sealing protection of the connector has specific size requirements for the cable at the beginning of the design.
With the same current-carrying cross-section, cables can have different outer diameters, such as shielded cables and unshielded cables, GB cables, and LV216 standard cables. The specific matching cables are clearly stated in the connector selection specification. Therefore, special attention should be paid to adapting to cable specification requirements when selecting connectors to prevent connector sealing failure.
(4) The entire vehicle requires flexible wiring: For vehicle wiring, all OEMs now have bending radius and slack requirements; based on the application cases of connectors in the entire vehicle, it is recommended that after the wiring harness assembly is completed, the connector terminal itself will not Force. Only when the entire wire harness is subjected to vibration and impact due to vehicle driving and the body undergoes relative displacement, the strain can be relieved through the flexibility of the wire harness. Even if a small amount of strain is transferred to the connector terminals, the resulting stress will not exceed the design retention force of the terminals in the connector.
Post time: May-15-2024