1. Ultrafast charging problem:
At present, charging is not as fast as refueling. During the National Day holiday, many users complained that electric cars had become "electric dads". In fact, the charging speed of high-power power battery is as fast as refueling, but the specific energy is low, which can not meet the requirements of long battery life. Nowadays, there are more and more electric vehicles with long battery life, which are full of energy-type power batteries that emphasize high specific energy. It is not easy to charge them at an ultra-fast speed.
For example, 350 kW ultra-fast charging, 5 minutes charging close to 30 kWh, there are many problems to be solved: the charging rate is too high, the battery can not stand it; The charging current is too large for the car to stand; The charging power is too high for the power grid to stand. Therefore, the battery itself should have fast charging ability, that is, a relatively high peak charging rate. The voltage of the on-board electrical system should be increased to 800 volts to reduce the total charging current during super-power charging. It is best to use the energy storage battery to discharge high power of 350 kW to reduce the load of the power grid, so as to facilitate ultra-fast charging.
2. Slow charging and car networking interaction
According to statistics, at present, 75% of the charging capacity of household electric vehicles is obtained through slow charging. With the rapid increase of the number of electric vehicles, slow charging will bring great pressure to the power load. There are now 400,000 electric vehicles in Beijing, which are used much more frequently than fuel vehicles. At least 20% of the traffic to and from work every day is electric vehicles, which will soon reach 30% and 40%. Charging after work, the power system can't stand it, this problem has appeared in Shenzhen and other places. Therefore, the era of disorderly charging is coming to an end, and then it will enter the stage of orderly charging, with a background to manage the charging and adjust the charging to a low power load range through the electricity price mechanism. Now Shenzhen has begun to demonstrate.
The information network that manages charging will intelligently dispatch the charging energy of the power grid, and the embryonic form of energy internet will appear, which is a great event. Ordered charging or unidirectional energy flow controls when to charge. Further development is two-way, and the battery of electric vehicle will charge and discharge.
A smart energy system integrating battery energy storage, light collection, storage and charging with electric vehicles as the core will be gradually introduced in China. It is expected that orderly charging will be the mainstay before 2025, and the interaction with buildings and microgrids will be developed from 2025 to 2030. The power system with renewable energy as the main body will be characterized by distribution and marketization. The basic policy of national power reform is to open both ends and control the middle, that is, to control the power grid, to open the user side and the power generation side, and to build a unified national power market. The charging and discharging of electric vehicles will also be a market. Charging and discharging is like buying and selling stocks. Collect if the electricity price is low, and sell if the electricity price is high.