Why Are Charging Outlets Critical to EV Innovation

You can easily judge whether a car is an electric car or a fuel car only by observing several designs on it, because the electric car has no exhaust pipe and no front grille, but an additional charging socket.

Charging socket is a component that electric vehicle consumers often (even every day) come into contact with, so its performance plays an important role in shaping consumers' preferences, ensuring the safety of electric vehicles, and accelerating the popularization of electric vehicles in the market.

Designing a reasonable charging socket can provide the charging power required by a large battery, shorten the charging time, and thus alleviate the mileage anxiety of consumers. The design of charging socket should also consider flexibility, expandability and durability. In this way, vehicle manufacturers will be able to apply this technology to vehicles all over the world. The Connector should also be easy to assemble and maintain, and easy to replace when necessary.

In short, the charging socket is destined to have a significant impact on the market acceptance of electric vehicles and the success of vehicle manufacturers in the field of electric vehicles.

In the next few years, most electric vehicle consumers will be new customers who purchase for the first time. For them, the charging socket will become a key factor in their new driving experience.

In the past, drivers drove into gas stations, filled up with gas in just a few minutes, and then continued their journey. Nowadays, electric car drivers must get used to longer charging time. At the fast charging station, the charging time will last from 20 to 60 minutes, while charging at home will take longer.

This is a series of new challenges for vehicle manufacturers. In order to alleviate consumers' anxiety about mileage, manufacturers install larger batteries for vehicles, which requires a charging socket that can safely provide larger current, thus shortening the charging time and optimizing the charging efficiency according to the temperature feedback of the charging socket.

At the same time, vehicle manufacturers also require the charging socket to be easy to assemble and install, and at the same time it can meet various requirements (including various regional standards, different electrical structures and vehicle platforms).

In addition, vehicle manufacturers must also consider that the charging socket should be able to withstand the test of time. Technicians of us company, Kable-X, will need a service-friendly design to avoid complicated and costly maintenance procedures, such as replacing the entire wire harness.

As a decisive factor of electric vehicle technology, charging socket needs intelligent design scheme to meet these challenges.

Most charging outlets will provide two charging interfaces. The first interface inputs alternating current (AC) into the vehicle charger, which then converts it into direct current (DC) and charges the battery; This method is usually only applicable to the situation of less than 11 kW and low current, so it takes several hours to be fully charged. In contrast, the second interface can use direct current (DC) to charge the battery, which is faster. For current cars, it usually takes less than an hour to complete charging.

Heat generation is the biggest obstacle to fast charging. The greater the current through the conductor, the more heat will be generated. At present, many vehicle manufacturers have issued standards, which require that the charging socket can continuously provide 500A DC current, and can provide 800A or even more current in a short time in the future. Unless properly managed, the heat generated by such a large current will cause damage to the components.

Manufacturers can use two means to meet this challenge. The first method is accurate and rapid temperature sensing. Generally speaking, in order to protect consumers who may touch the charging socket, the regulations stipulate that the total working temperature should not exceed 90C. With the advanced temperature sensing technology, the system can accurately track the terminal temperature, and prevent the temperature from soaring to more than 90 degrees.

In order to provide the maximum charging power for the battery, it is very important to provide accurate temperature sensing feedback for the system. The challenge is that although the temperature sensor can be embedded in the charging socket, according to the requirements of electrical insulation safety, the sensor cannot directly contact the heat source. This separation will lead to the delay of induction time and a certain temperature difference between the heat source and the sensor.

If the data is not accurate enough, the charging system can't reach its full potential. The charging system software must control the charging rate conservatively to solve the problems caused by time delay and temperature error.

Some designs can make up for these limitations, so that the error is as low as 3C and the time delay is negligible. Through these designs, the system software can realize real-time adaptive charging and always keep the power at the highest level.

The second way to solve the overheating problem caused by fast charging is to adopt cooling technology.

Although many infrastructure charging stations are equipped with cooling measures, because the DC charging terminal and bus are located inside the charging socket of the vehicle, these cooling measures have little impact on the vehicle. On the other hand, the terminal wing harness size of the industry standard is not enough to support the charging power level that the vehicle manufacturers hope to achieve in the future, which also poses another challenge. Adding a thicker cable harness can draw heat away from the socket terminal, but it can only play a role to a certain extent when there is a difference between the size of the terminal and the cable.

Only cooling the charging terminal can achieve the required power level in the future. This cooling can be passive cooling or active cooling.

Passive cooling is carried away by the "potting" material around the power terminal. However, adding potting materials or heat-absorbing devices may increase the difficulty of building wiring harnesses or repairing interfaces. On the other hand, although the potting material or heat sink can take away the heat of the terminal, this passive cooling method can only dissipate heat through the surrounding air, and can't further cool down. As a result, most of the heat will reside in the material block, especially when the ambient temperature is high.

Comparatively speaking, active cooling can make the system accept more current for a longer time. Designers can lower the temperature by letting the coolant flow near the charging terminal. A cooling plate is connected to the bus bar adjacent to the charging terminal (or pin), so that the cooling liquid can take away the heat through the cooling plate. When active cooling is adopted, the air around the socket becomes less important; That is to say, the temperature rise is only related to the temperature of the coolant, and is largely unaffected by the ambient temperature.

The test conducted by Ampofo shows that when the current is 500A, this technology can limit the temperature rise of the terminal to an acceptable range for a long time. Without active cooling, the running time of 500A current will be limited to 10 to 15 minutes.

Combined with real-time temperature sensing, active cooling technology allows vehicle manufacturers to control the maximum power input to the battery. Although this will increase the complexity and cost to a certain extent, many systems in the automobile also have cooling requirements, such as inverters, batteries, converters and other power electronic devices, so there may be shared coolant available in the automobile.

Running more current for a longer time is the key to shorten the charging time. The simplified example (ignoring the derating effect of the battery) shows that for electric vehicles, the battery of 100 kWh can be fully charged within 30 minutes at a voltage of 400V (the voltage of electric vehicles is expected to reach (400V) in the near future and a current of 500A. With the development of some car platforms to 800V voltage, the charging time may be shortened to about 10 minutes, which is almost equivalent to the current time of stopping at a gas station.

At the same time, global vehicle manufacturers are seeking to realize vehicle electrification in various markets. In order to achieve this goal effectively and economically, they will need charging socket technology suitable for various regions and various automobile configurations.

One requirement of flexibility is to adapt to different regional standards. North America, Europe and Asia all implement different charging interface standards for AC and DC vehicles. Adhering to the industry's consistent design philosophy, vehicle manufacturers should consider charging sockets equipped with various general components and applicable to various standards. They should also consider compatible charging sockets in different regions on the basis of the same car configuration and hardware, which is also a key issue that global car platforms must consider.

Another requirement for flexibility is that the same charging socket technology should be applied to different models, although the electrical architecture and physical structure of each model are different.

For example, depending on the physical configuration of a certain vehicle model, the high-voltage cable or bus may need to be routed to the left or right when packaging, while in other vehicles, it is required to route the cable straight down, or even directly lay it in the carriage return. If the charging socket can easily support various wiring directions on different platforms, vehicle manufacturers will have the opportunity to achieve economies of scale, because they can reuse the core components of the socket on multiple platforms.

Similarly, the shape and installation position of the socket panel on different models may be different. The whole vehicle manufacturer may wish to install different logos or configure LED lights on the panel. Modular design can adapt to the above situations and keep common components.

Manufacturers may also choose to use high-voltage bus instead of cable to connect the DC end of the charging socket to the battery. Compared with cables with the same cross-sectional area, high-voltage bus can carry more current, so it is increasingly favored. They can also solve the problem that cables used in some complex spaces in the car are difficult to bend and wire, and are also conducive to the realization of automatic assembly.

Another problem that vehicle manufacturers should consider that may have a significant impact on the production cost is how to facilitate the first-level suppliers of assembly wiring to start production.

Charging socket is a complex device, which contains many parts and connectors, and these parts have both low voltage and high voltage. Some upstream suppliers deliver charging sockets to harness suppliers in the form of scattered and unassembled parts. Although the price of these sockets may be lower in the upstream of production, the overall cost is concentrated in the downstream of production due to longer working hours, more complicated wiring design and potential quality problems. In contrast, modular design can significantly reduce the packaging quantity of the charging socket, not only reducing the total cost, but also ensuring the quality.

Electric vehicles have become the market choice, and the electric vehicle market is booming in generate. According to the data of Boston Consulting Group, in just 14 years, electric vehicles will account for 45% of the total sales of new cars. With the surge in sales, the service gap will follow.

A recent study shows that only 3% of automotive technicians know how to repair electric vehicles. Many repair shops are not equipped with corresponding maintenance equipment, or think that there is no need to train employees, because compared with gasoline or diesel vehicles, the maintenance requirements of electric vehicles are smaller.

In addition, technicians may be discouraged by the "high voltage" warning signs everywhere on electric vehicles. Although electric vehicles have low maintenance requirements, they still need maintenance due to frequent use (even improper operation). The charging socket is one of the most frequently used components, which will cause normal wear and tear. Although the current interfaces are durable, they may also be damaged by improper use forms such as cleaners, water cannons and violent operations. Almost every manufacturer can prove that human beings have amazing creative ability in inventing products that improve the quality of life, but they also have comparable destructive ability.

Considering this point, the whole vehicle manufacturer should regard the charging socket as a component that needs convenient maintenance, and its design and assembly should allow maintenance technicians to replace it without dismantling the entire Wiring Harness system.

Configuring a suitable connector for the socket can solve this problem. It allows technicians to remove the socket parts through a series of simple steps such as unplugging the cable and removing the bolts of the bus. Adding a straight-through connector to the AC charging harness can easily replace the socket terminal. This method can replace the time-consuming and expensive maintenance procedures, while avoiding damage to the rest of the charging harness.

With deep expertise in high-voltage electrification, Kable-X has a deep understanding of the special requirements of the next generation electrical architecture. We know how to efficiently manufacture electrical components, make use of cutting-edge technologies to achieve maximum benefits, and build flexible and durable innovative solutions. Today, we apply this expertise in the field of charging sockets.

For decades, consumers have been measuring vehicle performance based on the time it takes for a car to accelerate from a standstill to 100 kilometers per hour. With the advent of the era of electric vehicles, the length of charging time will be an important indicator to measure the performance of electric vehicles. If an owner's sports car takes 30 minutes to charge, he may envy another sports car that can be charged in 10 or 15 minutes and hit the road again. Speed is still an important measure, but now people are not only concerned about the acceleration of the car, but also how quickly the car can get back to the road after it leaves the road.

In this comparison, the charging socket will play an important role. A charging socket that can safely and quickly charge high-power batteries will become an important part of building high-quality vehicles for the future.