Compatible with other standard Chaoji charging standard design

Currently, ChadeMO3.0 is also in the pre-release stage, and the official release will be this year together with the China Electricity Council. So the information we can find now is some ideas in designing and improving this set of standards, and there are many things here that deserve our attention.

01 Part 1 Design of the Steering Circuit                        

As shown in the figure below, due to historical reasons, the control pilot circuit is differentiated at the DC level. CCS1 and CCS2 are based on the AC pilot circuit, and the communication is completed based on PLC communication; the DC pilot circuits of ChadeMO and GBT are separated from the AC, so they can be considered independently. After the basic connection is established, CAN communication is enabled for subsequent content. So the question here is how to realize many functions in the future:

1) Compatibility with several global standards. China, Europe, and the United States are the three major electric vehicle markets in the world. The potential market in Southeast Asia, which is gradually increasing, needs to be compatible with a solution. If the interface and guidance circuit are taken into consideration, the vehicle side should configure this function.

2) The original AC charging involves orderly charging and V2X. Due to the relatively simple interaction, it is difficult to achieve the next step of intelligent work. The charging interface of Chaoji also provides certain support for subsequent small DC charging.

Figure 1 Steering circuit of electric vehicle 

What the designers want to do is to make the guidance circuit on the vehicle side as consistent as possible with most vehicles, especially to design the CC1 and CP circuits consistent; CC2 makes the vehicle more identifiable.

Figure 2 Chaoji control guidance circuit

The most important thing for forward compatibility is to provide an impedance matching solution for the resistance of a simple enough Chaoji plug through impedance adjustment provided by the Adapter, so that Chaoji vehicles can be connected to ChadeMO2.0, GB/T2015 and CCS circuits after being equipped with the Adapter.

Figure 3: Design that takes compatibility into consideration from the very beginning and incorporates Adapater considerations 

During the startup and docking process, we also took into account the differences between GBT27930 and Chademo, and made a set of compatible initial charging startup timing solutions. 

Figure 4 Compatibility considerations for charging control protocols 

According to this design direction, if European car companies directly adjust CCS2 (developed to version 3.0) to Chaoji and make the following design, and add the following guidance, this is also possible in the future when the sales of European pure electric vehicles in China increase and high-power charging facilities are required. If such development is carried out, DC and AC must be handled separately, and even most car companies in the future will directly cancel AC on BEV and use small tributaries to carry out the operation directly at the same time. 

Figure 5 The possibility of CCS2 moving towards Chaoji also exists in the future 

Note: The 120V low-voltage DC solution made by Chademo below is still very important for the pure electric significance of A00. Removing the OBC of the A00-level pure electric car and replacing it with a low-cost charging system is very promising. Japan's promotion of K Car electrification at the A00 level is Japan's hope for pure electric. Otherwise, relying on the current Japanese car companies' models in the A-class and compact SUVs, there is not much hope. 

Figure 6 Japanese proposal for small DC within 120V 100A 

02 Design considerations for 400A and 30 minutes                

From the current perspective, we initially moved up from the 250A rated specification, so the next step, whether it is the electrical connection design in the car or the pile, is to consider the feasibility of the entire electrical connection by considering the continuous 400A @30 minutes of passability. Now let's look at the 95mm2 wire configured in the car. Under the current conditions of using aluminum wire, Tesla has reached 700A in a few minutes, so controlling the temperature rise on the overall circuit is a very critical thing. It is expected that the design of charging currents of different specifications of 300A, 400A and 500A will be formed later. 

Note: Metal connectors will corrode faster when snow removal agents are applied in the north, so the layout and life of the DC fast charging connector are worth considering. 

Figure 7 Temperature rise control at 400A fast charge 

Summary: We look forward to the release of this set of standards in the middle of the year. Once it truly enters the implementation stage, the competition for fast charging power and speed of pure electric vehicles will also be further carried out after the two main lines of driving range and price reduction.