XJ Group Corporation

Rapid battery swapping, thanks to connectors from Phoenix Contact


Intelligent mobility: China opts for electrically operated public transport

The XJ Group Corporation produces and supplies power, generation, transmission, and sales systems. The company also offers direct current transformers, protective equipment, as well as automation technology and electrical equipment for rail traffic, intelligent smart meters, AMR, and distribution network automation systems.

Customers include supply companies in China, Turkey, Indonesia, Brazil, Thailand, and India. The company was founded in 1947 and its headquarters are based in Xuchang, China. Since 2011, the XJ Group Corporation has been operating as a subsidiary of China Electric Technology Equipment Co., Ltd..


Electrically driven buses  

The replacement of batteries in the bus is carried out fully automatically

E-Mobility is already an everyday phenomenon in China. In the harbor city of Qingdao, East China, public transport will soon take the form of electrically operated buses in order to reduce exhaust gas emissions.

In order to keep the downtimes of buses to a minimum when charging their batteries, the planners decided to use a concept which replaces batteries, namely “battery swapping”. The empty batteries are replaced by fully charged ones while the bus is at a changing station, with a loaded robot on each side of the bus. The battery units are swapped for newly charged ones in around seven minutes, and the bus can set off again. The XJ Group Corporation, based in China, was looking for a suitable connector for the battery units in their fleet of electric buses.


Connectors from Phoenix Contact  

Connectors from Phoenix Contact transmit 400 A and are vibration resistant

Battery replacement systems rely upon 100 percent reliable and robust plug-in systems, as every minute of downtime is costly. Phoenix Contact developed a plug-in unit especially with these electric vehicles in mind, as it had to meet the demands placed on it by continuous use.

Since the batteries are placed under high stress from multiple charges and use during the course of a day, the charging process must be gradual - but at the same time, fast. Using an integrated data module, the temperature can be monitored in conjunction with the targeted management and the charging process monitoring, in order to prevent potential overheating.

As parking the large buses extremely precisely is no easy feat, deviations in vehicle positioning are compensated for by self-centering, spring-damped guide pins during the plug-in process. These function as vibration damping during the journey and establish fail-safe connectivity. The connection system is designed for currents up to 400 A and voltages up to 750 V, thanks to its dimensions and material properties.

Since then, over 6000 plug pairs have been delivered to China. The batteries of around 40 buses are replaced two or three times each day at the changing station. In total, more than 100,000 battery replacements have taken place up to now. Phoenix Contact connectors have continued to play their part faultlessly.


The DC replacement battery concept from Phoenix Contact is particularly suitable for utility vehicles used in local and municipal authorities as well as for forklift trucks, transport vehicles, and passenger transport vehicles. The system transmits currents up to 400 A as well as voltages of up to 750 V DC.

Thanks to tolerance compensation for the plug-in process and vibration damping during the journey, the connection system ensures safe contact even at high mechanical load – and this is for more than 10,000 insertion/withdrawal cycles. The battery swapping concept also has an integrated data module for charging state monitoring and enables operators to monitor all charging processes and to eliminate downtimes caused by malfunctions.

Phoenix Contact UAB

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