Application scenarios for the development of high-voltage cables for electric vehicle connections

Product description: Based on the experience level of cable production and testing, since the current is fluctuating, although the peak power demand point of the entire drive is relatively high, the duration will only last for 10s and then drop. The total current can be completed by using the root mean square design. In the DC fast charging design, the process of power dissipation is the heating of wires, cables and contact resistance, and changes with the increase in temperature during operation.

Considering the actual situation, the entire temperature connection point needs to be controlled below 100 degrees. The main reason is that exceeding one temperature will make the anti-corrosion coating of the conductor unstable. Similar to the temperature rise problem caused by the contact resistance and crimping resistance of the charging cable and connector below, it will also appear inside the battery we mentioned above. If it appears at the battery connection, it will have a great impact on the battery.

Variation of the first path: Since under this path, we can also divide the battery into two 400V*2 configurable systems.

In the short term: the configuration includes 400V high-voltage bus, 400V/12V DC/DC, 400V inverter, 400V air-conditioning compressor, and 400V on-board charger.

The long-term approach is to connect the two modules in series to form an 800V system. In my personal judgment, since the VDA-based module can also achieve the conversion from 4P3S to 2P6S, if we build the entire battery system based on the VDA 355/390 module, the main method is to change the module configuration and electrical connection in the battery system. . The parallel connection of the two modules is at the expense of the current higher cost and higher energy consumption. This problem requires us to compromise and balance in the design.

One method is to combine the two batteries into a voltage configuration according to the conditions of external fast charging, divided into two battery modules A and B, with a voltage of 400V. In the case of discharge and AC charging, the two are connected in parallel. , the high-voltage DC bus is 400VDC; in the case of high-power charging, the two battery modules A and B are connected in series, the system voltage is 800VDC, and only the charging part is connected. Under fast charging conditions, the high-voltage electrical system is 800VDC, and the electric power system under other conditions is 400VDC, basically maintaining the original structure. There is also a way to keep the battery in parallel, similar to the Mercedes-Benz EQC, waiting for an opportunity.

Second path: 800V battery high-voltage system. The battery system uses 800V high voltage, and the electric powertrain system, including electric drive, power electronics, charging system, etc., also uses an 800V system. At present, this architecture can actually only be carried out on a limited number of vehicles, and major car companies are currently evaluating the current progress. I personally think that the main reason is that the current cost of SiC devices is too high, which increases the cost of all high-voltage electrical components such as inverters, DCDC, on-board chargers, PTCs, electric compressors, etc.

Most companies are evaluating the conversion schedule on the main inverter, which is actually based on the expansion of the SiC material side and further slowly evolving on the road to reducing the cost of semiconductor technology. At present, only the cost of 400V-based SiC devices used by Tesla is relatively affordable, and only high-priced pure electric sports cars such as Porsche can digest this cost.

Of course, instead of understanding the specific product specifications for actual applications, it is better to let us provide you with cable details solution services. Welcome to: OMG EV cable