In The First Year Of High-voltage Fast Charging, Charging Piles Welcome New Opportunities For Development

In the First Year of High-voltage Fast Charging, Charging Piles Welcome New Opportunities for Development
 

The charging pile is a device that supplements electric energy to new energy vehicles (including pure electric and plug-in hybrid). Its function is similar to the gas dispenser in the gas station. It can be installed in places such as roads, office buildings, shopping malls, public parking lots and residential parking lots. , charging various types of new energy vehicles according to different voltage levels. The fast-growing new energy vehicle market has increased the demand for charging piles. According to the data of the China Automobile Association and the Charging Alliance, by the end of 2021, the number of new energy vehicles in the country will be 7.84 million, a year-on-year increase of 59.3%; the number of charging infrastructure nationwide will reach 2.617 million, a year-on-year increase of 55.7%. The rapid growth of new energy vehicles The market has increased the demand for charging piles. In the future, as the penetration rate of vehicle electrification continues to increase, the market demand for charging piles will further expand.

High-voltage fast charging has become an important solution to the charging problem

In order to improve the charging experience of consumers, we can continue to improve the vehicle-to-pile ratio or significantly reduce the charging time to meet the needs of consumers for fast charging. In terms of fast charging, there are currently two technical routes: increasing the charging current and increasing the charging voltage. From the perspective of different practices, high-voltage fast charging can achieve maximum power charging in a wider range, and can better match future fast charging needs:

1) High current route: low degree of promotion and high requirements for thermal management. According to Joule's law (formula Q=I2Rt), the increase of current will greatly increase the heat in the charging process, which requires high heat dissipation. The use of thicker wire harnesses has higher requirements for heat dissipation technology, and can only achieve a maximum charging power of 250kW at 5%-27% SOC. High-efficiency charging does not cover the whole process. At present, domestic car manufacturers have not made significant customization changes in the heat dissipation scheme, and high-current charging piles largely rely on self-built systems, resulting in high promotion costs.

2) High-voltage route: It is a mode commonly used by car manufacturers at present, which can take into account the advantages of reducing energy consumption, improving battery life, reducing weight, and saving space. Currently limited by the withstand voltage capability of silicon-based IGBT power devices, the fast charging solution commonly used by car companies is a 400V high-voltage platform, that is, a charging power of 100kW can be achieved with a current of 250A (100kW of power can travel about 100km for 10 minutes). Since Porsche launched the 800V high-voltage platform (achieving 300KW power and reducing the high-voltage wiring harness by half), major car companies have started research and layout on the 800V high-voltage platform since then. Compared with the 400V platform, the 800V voltage platform has a smaller operating current, thereby saving the volume of the wiring harness, reducing the internal resistance loss of the circuit, and improving the power density and energy efficiency in a disguised form for a lithium battery charging cabinet.