Connectors are used in every automobile, the device uses electrical and optical signals to connect, disconnect and convert with the help of its control of the corresponding mechanical force. In order to achieve the corresponding circuit or optical channel conversion of a functional component. And with the ECT electrical and optical signals can also effectively prevent its signal distortion and the corresponding energy loss, and thus ensure the efficiency of the conversion.
At the same time, the connector in the new energy vehicles in the application of high-voltage connectors are mostly used in its terminal applications. And thus enhance the corresponding transmission sensitivity performance. While the advanced nature of the device will also affect the level of development of automotive transmission technology.
Background of application
In recent years, the world’s pollution has intensified, and in order to cope with this serious situation, China has advocated green development. The automotive sector is no exception, which has led to significant progress in the new energy vehicle industry. In the process of this industry development, high-voltage connectors as one of the core components, play a huge role and play an unparalleled value. It is used in the whole vehicle and charging facilities of new energy vehicles.
The device mainly consists of contact parts, insulator, shell, accessories and other parts.
Among these parts, contact parts are its core, and also shoulders the line, the system in driving light, electricity and other signal connections, so it can be seen as its central components.
And insulator when the insulation protection role, mainly is isolated from the external environment.
The shell is fixed as well as auxiliary protection, even as a base.
The final accessories are more extensive, and need to be set up according to the specific application requirements to target.
Of course, the main assistance to complete the connection cable or other parts of the protection. And it is also an important auxiliary unit to ensure that the requirements of the working environment.
And to achieve the connection function is its central contact parts, any poor contact is the source of failure. This paper concludes that more than 70% of the causes of system failure or malfunction in new energy vehicles are caused by the failure of this type of component. And in this, more than 40% is due to contact failure. This shows the importance of contact parts in new energy vehicles.
Material, performance and structural requirements of contact parts
In working on aspects related to high-voltage connectors in new energy vehicles, it is not only necessary to avoid similar patents, but also to find suitable components. And the core structure of this is its contact parts. For them, especially the structure, performance, and material of their jacks have a significant impact on the corresponding performance.
The structure of the contact parts
The overall structure of the connector of new energy vehicles is not complex, basically using a metal shell of the circular connector. And with the development of various engineering materials in recent years, plastic connectors are also more common. But the basic structure is basically the same, generally include pins and jacks are two parts, through the plug to achieve connection.
The general use of pins in order to pursue its connection performance, are basically using rigid pins, flexible jacks. Of course, for some of the existence of special needs of the contact parts also need to be plated, silver or gold plating mostly.
Performance of electrical connector contact parts
The basic performance of electrical, mechanical, environmental resistance of the three. The former are to meet the contact resistance, insulation withstand voltage, insulation resistance of these three requirements, which is to ensure the reliable transmission of light and electrical signals to protect. The mechanical aspects need to consider the insertion and removal force, mechanical life factors. Most of the components of the type of its overall life is more than plugging 50 times.
Materials of electrical connector contact parts
Pins and jacks material should have high mechanical strength and elasticity. They should prevent damage,loosening and possess strong contact force. Their fatigue resistance,processing and molding abilities need to be guaranteed. Brass is commonly selected as pin material.
Factors affecting the reliability of contact parts
1. Contact form
Contact forms are point, line and surface. Usually it is point contact. But when its range is expanded to a certain extent both line or surface contact. Relatively speaking, the more contact points, the corresponding contact resistance will be smaller, and the actual use will be better.
2. Contact pressure
In general, all forms of contact have a higher instantaneous contact resistance. And as its contact area and the corresponding number of points purpose to increase. Because the corresponding contact resistance is constantly reduced, the transient voltage will be reduced. This is especially important in the selection of jack elastic structure.
3. Temperature influence
When the operating temperature of the contact rises to a certain level, the hardness of the pin and jack materials will be reduced with the increase in temperature. But the lower the contact resistance, the less obvious this problem. The higher temperatures will accelerate the oxidation of the contact surface of the two. Which in turn will aggravate the aging, so it is necessary to carry out some suppression.
4. Corrosion of metal substances
There are two kinds of chemical and electrochemical corrosion. Mostly due to external environmental pollution caused by this problem. Such pollutants will cause the metal surface oxide layer, which will cause its corresponding contact resistance to rise.
5. Material properties
Pin and jack material properties for the final contact effect and life are significant impact. The two properties can include material resistivity, hardness, chemical, high temperature and other aspects of the relevant properties. This, the most direct influence is the resistivity of the material. The next influencing factor is both hardness.
6. Surface quality
In comparison, a flat and rougher contact surface can effectively increase the number of contact points between the two, and the friction is also greater, which can effectively remove the oxide layer, so that the contact resistance can be effectively reduced.
Analysis of the characteristics of common contact parts in new energy vehicles
Analysis of the characteristics of the contact parts
The reliability of electrical connectors is closely related to their own internal structure, of which the contacts are the core. Pins and jacks are the main structure of the contacts, of course, in order to achieve the expected electrical, resistance, reliability, the type of choice is also critical.
The specific application of new energy vehicles corresponding to the use of high-voltage connector requirements are relatively more. Because in order to respond to the various unpredictable conditions that may arise, we choose the basic performance and structure of the contact parts need to have a certain degree of relevance, the specific characteristics of the selected structure as shown in Table I.
| Basic Features | Advantages |
|---|---|
| The small diameter pins are as short as possible, and the pins are protruding and the jacks are recessed into the insulator. | Can avoid bending and deformation of the pins and jacks when inserted. In general, the diameter of the jack is larger than the pin. As the diameter of the pin and jack decreases, the strength gradually decreases, and the life of insertion and separation is shortened. |
| The end of the pin is spherical or tapered bevel. | Due to manufacturing, assembly errors, connectors in the jack and pin coaxiality can not guarantee the exact same, in the process of inserting the spherical or tapered will help the jack pick up the pin, and has the role of correcting the bent pin. |
| Jack ends are generally chamfered to form a flared mouth, can be installed inside the elastic reed, slotted jack can increase the sheath. | Horn mouth to facilitate the jack to pick up the pin and correct the role of bent pins, in addition to slotted jacks, the general jack is limited to prevent the diameter of the pin into the jack damage to the elastic reed, as well as bent pins inserted diagonally into the jack, resulting in poor contact. |
| Jack and pin contact part of the surface should be polished. | Smooth surface can increase the actual contact area between the pin and the jack, improve the quality of the plating, reduce the wear and tear when inserted and separated. |
Table I Basic structural characteristics of contact parts
Of course, if the structure of the pin is basically the same, but the corresponding production materials will also exist some differences, in our country its basic materials are mostly used copper or copper alloy; corresponding to several jack forms as shown in Table II. And Table II also briefly describes the main features of the corresponding.
| Contact Form | Features | Usage Ratio |
|---|---|---|
| Crown spring type jack | 1.Bronze plated multi-springs are placed inside the copper jack base and the crown springs are connected with bevels so that the elasticity will not fail. 2.The life span is 5000-10000 times, the plugging force is 3-10 Newton, the contact resistance is 0.2 milliohm or less, and the rated current is between 13A and 1000A. |
30% |
| Torsion spring type jack | 1. twisted wire twisted spring connectors to increase the contact area, contact resistance is reduced, the electrical performance improved, while also improving the vibration resistance. 2. The deformation method from the original only radial deformation to twist deformation around the shaft and twist micro-deformation between the twisted wires, thus improving the life of the jack. |
35% |
| Touch finger type jack | 1. Finger jack in the conductive – thermal conductivity characteristics, there is a high continuous current-carrying force and short-circuit current withstand. That is, through the multi-point contact can have a lower contact resistance, especially in the contact finger seat with two holes can make the temperature rise lower. 2. In terms of structure and mechanical characteristics, the equivalent current conductivity and electromagnetic field characteristics, because there is no need to add additional shielding, the design size can be smaller, simple structure, quick installation, and in the contact finger stroke is small to allow a larger installation coaxiality, as well as a wider range of applications. 3. High contact reliability, gentle insertion and removal, high mechanical life, and moderate manufacturing cost. |
35% |
Table II Summary of the characteristics of contact parts
The choice of contact parts
The above three types of jacks are the most basic conditions for the selection of contact parts. New energy vehicle for the above three types of jacks are generally more suitable. But most of the cases are mostly required according to the actual needs of customers in accordance with their given size to produce or customize the corresponding connectors.
And the body material is not always copper or copper alloy, beryllium bronze. Silver-plated plug-ins have now become more common. So the choice of centralized contact parts is also required according to the actual needs of targeted selection.
Summary
New energy vehicles with high-voltage connectors selected contact parts need to work under relatively harsh working conditions. Usually, we must first ensure the reliability of the application, followed by the need to consider the economy, process and other related factors, according to the actual needs of customers, there are trade-offs.
With the gradual maturation of this type of technology, the corresponding future pursuit of performance, the quality of the connector and performance requirements will gradually change. High performance, low cost has become an important development trend. This is also the ultimate pursuit of research and development of highly reliable electrical connectors.