Standard and application overview of New energy high-voltage connectors

1.Composition of new energy high-voltage connectors

New energy high-voltage connectors mainly include: housing (divided into male and female ends), terminals (including male and female terminals), shielding covers, sealing components (such as tail, half end, wire end and contact part seals), tail protection cover, as well as high-voltage interlocking system and CPA system and other structures.

2.Standards of high-voltage connectors

The standard system of high-voltage connectors is mainly based on industry standards, covering safety regulations, performance and other requirements. At present, the mainstream connector design will refer to the LV series standards jointly formulated by the four major European OEMs-Audi, BMW, Daimler and Porsche. In North America, it mainly follows the relevant standards of SAEuscar, among which the commonly used standards such as uscar2 and 37 are formulated by the wiring harness connection organization EWCAP jointly established by the three major OEMs of Chrysler, Ford and General Motors. It is worth mentioning that since its establishment in 1994, the organization has updated the SAE-USCAR 2 standard in 2008 to adapt to the rapid growth of the HEV market, and increased the voltage level from the original 20V to the current 600V.

In Europe, automobile OEMs such as VW, BMW and Daimler also played an important role, jointly formulating industry standards. Germany, as a leading country in the automotive industry, has made significant contributions to the formulation and promotion of standards. It is worth mentioning that VW's interests in relevant industry standards have been fully reflected. In addition, the AK working group has further refined the requirements such as the installation interface size, which fully demonstrates the consistent rigorous style of European and American OEMs. At the same time, industry giants such as TE, Amphenol, Kostal, Molex and Delphi have also actively participated in and contributed to these standards.

In response to the GB standard, we have also formulated specifications for high-voltage wire harnesses and high-voltage connectors accordingly, but these standards still need to be further improved and optimized, and the specific details will not be elaborated here. It is worth noting that high-voltage connectors are usually not available as independent products on vehicles, but are combined with wire harnesses, so the standard requirements of wire harnesses are also crucial. In the industry, the SAE j1742 standard is widely used as a reference.

With the popularization of new energy vehicles, we are increasingly exposed to various types of new energy vehicles in our lives, such as extended-range electric vehicles, hybrid vehicles, fuel cell electric vehicles, etc. These models are inseparable from a large number of connectors. Compared with traditional fuel vehicles, electric vehicles have a high voltage and high current characteristics, which greatly increases the demand for high-voltage connectors on new energy vehicles. There are many types of connectors, for example, they can be divided into round and rectangular according to shape, and high frequency and low frequency according to frequency. However, this article will focus on the high-voltage connectors of new energy vehicles for in-depth discussion and sharing.

3.Connection categories

In new energy vehicles, there are various ways to connect the wiring harness of high-voltage connectors. We mainly divide them into two categories: one is the fixing method of direct bolt connection, and the other is plug-in connection.

Bolt connection is a common connection method. Its advantage is high connection reliability because the mechanical force of the bolt can withstand automotive-grade vibration. In addition, its cost is relatively low. However, this connection method also has some shortcomings, such as the need for a certain amount of operating and installation space. In today's increasingly compact space in the car and the increasing development of regional platformization, this connection method may not be suitable. At the same time, from the perspective of mass production and after-sales maintenance, it also has some challenges. In addition, the more bolts, the higher the risk of human error, which is also its inevitable limitation.

Nevertheless, we can still see this connection method in the early Japanese and American hybrid models, as well as the three-phase motor lines of some current passenger cars and the battery power input and output lines of commercial vehicles. This type of connection usually requires the use of an external box to achieve other functional requirements such as protection, so whether to adopt this method requires comprehensive consideration of the power line design layout and after-sales maintenance requirements of the entire vehicle.

In contrast, the plug-in connector ensures the safety of the electrical connection by connecting the two terminal housings, thereby achieving a smooth connection with the wiring harness. A major advantage of this connection method is its simplicity, which can be completed by manual plugging, so it can effectively save space, especially in a small operating space.

With the increase in cable cross-sectional area and current, plug-in connection has also undergone technological innovation. The direct contact method of male and female ends used in the early days has gradually been replaced by the method of adding elastic conductor contact material in the middle. This contact method using elastic conductors is more suitable for the transmission of large currents. Its excellent conductive materials and carefully designed elastic structure help reduce contact resistance and ensure the stability of large current connections.

There are many types of intermediate elastic conductors, commonly referred to as "contacts", in the industry. Common ones include spring type, crown spring, leaf spring, wire spring and claw spring, each of which has unique characteristics and application scenarios. In addition, there are spring type, MC strap type and ODU wire spring type, and their selection depends on specific application requirements. Here, we will not elaborate on the specific introduction of each contact, but their application and importance in high current transmission cannot be ignored.

In actual applications, we observe that there are two main plug-in methods: circular and sheet type. In China, many models use circular plug-in methods, especially 8mm and above high current connectors produced by brands such as Amphenol TE. As for sheet type plug-in, its representative products such as Kostal's PLK contact have been widely used in early Japanese and American hybrid models, such as early Prius, TSSLA and some parts of BMW Bolt all use this design. From the perspective of cost and heat convection, sheet type plug-in does have advantages over traditional circular spring type. However, the choice of plug-in method depends not only on the actual application requirements, but also closely related to the design style of each company.

4.The Importance of high-voltage connectors in new energy vehicles indusctry

The high-voltage connector of new energy vehicles is an important component of new energy vehicles, mainly used for the connection between the battery management system and the electric drive system. It has the characteristics of carrying high-voltage current and working in high-temperature environment, which can ensure the stable transmission of current and ensure the full operation of the vehicle.

The high-voltage connector of new energy vehicles plays a key role in new energy vehicles. First of all, it is a bridge between the battery management system and the electric drive system, responsible for transmitting high-voltage current from the battery to the electric drive system to complete the function of driving the vehicle. During the high-voltage current transmission process, the high-voltage connector can stably transmit the current to the target position to ensure the normal operation of the system. Secondly, the high-voltage connector also plays a role in safety protection. Since new energy vehicles use high-voltage current, if the connector quality is not good, it is easy to cause current leakage, arc, short circuit and other problems, resulting in vehicle failure and even fire and other serious accidents. Therefore, the high-voltage connector needs to have good insulation performance and waterproof and dustproof performance to ensure the safety of the vehicle

The design of high-voltage connectors for new energy vehicles needs to consider many factors. First of all, it needs to be able to withstand the transmission of high-voltage current, and materials that can withstand high temperature and high pressure, such as silicone and glue, need to be selected. Secondly, the design of the connector needs to be compact and easy to install and repair. Since the size of new energy vehicles is relatively small, the connector needs to reduce the size as much as possible and improve the compactness of the connector while ensuring quality. In addition, the connector also needs to have good waterproof and dustproof performance to ensure that it can still work normally in harsh environments. In addition, the connector also needs to have high reliability to ensure that there will be no failures during long-term use.

The future development direction of high-voltage connectors for new energy vehicles is intelligence and integration. With the development of smart cars, high-voltage connectors also need to have intelligent functions, such as information exchange with vehicle control systems and automatic fault detection. In addition, with the popularization of new energy vehicles, high-voltage connectors need to be more in line with industrialized production requirements and achieve high-standard and high-quality production. To this end, the production process of high-voltage connectors needs to be fully automated and integrated to improve production efficiency and quality.

In short, high-voltage connectors for new energy vehicles play a key role in new energy vehicles. It not only carries the transmission of high-voltage current, but also has the function of safety protection. The design of the connector needs to consider factors such as material selection, tightness, waterproof and dustproof performance, and needs to be intelligent and integrated in future development. Only by continuously improving the quality and reliability of connectors can the safe operation of new energy vehicles be guaranteed.

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