New energy vehicles represent the future trend of automobile development. However, due to limitations in basic charging infrastructure and the driving range of pure electric vehicles, sales of electric vehicles have not been high. Of course, major automakers are also working on increasing the driving range of their electric models or improving charging methods through technological iterations.
Consumers buy electric vehicles mostly because they have a rigid need for a vehicle, but are limited by local license plate policies. However, the actual experience after purchase is generally average, especially for users who live in areas without charging stations, who can find charging to be quite painful.
Limited driving range and long charging times seem to have plunged new energy vehicles into a slump. How can these problems be solved? One approach is to increase battery packs to extend the driving range of electric vehicles; another is to improve battery technology and increase battery capacity; and yet another is to increase the charging efficiency of electric vehicles and shorten charging time… Among these, shortening charging time is currently the easiest technology to achieve.
Currently built charging stations support two charging modes: slow charging and fast charging! This is similar to charging our mobile phones, which has two modes: fast charging and slow charging. In fast charging mode, the battery can be fully charged quickly, at least 40% faster than slow charging. The concept of charging cars is similar, but the efficiency is far superior to that of mobile phones.
However, car owners need to understand that fast charging and slow charging are two different concepts. Slow charging uses AC power, typically taking 6-8 hours to fully charge, and this charging method minimizes battery damage. Fast charging, on the other hand, is an emergency charging method using high-power DC power (though AC fast charging also exists). This DC charging voltage is generally higher than the battery voltage, requiring a rectifier to convert the AC power to DC. This places higher demands on the battery pack's voltage resistance and protection, and the charging current is ten to dozens of times higher than conventional charging current. A large number of electrons flow from the positive to the negative electrode at extremely high speeds. Fast charging typically charges the battery to 80% in 30 minutes, and some automakers have achieved breakthroughs, reaching 80% in just 5 minutes! Such charging efficiency is astonishing, but a question arises: will such fast charging affect the car battery? After all, the battery in an electric vehicle is one of the three major components of a regular car.
Theoretically, it will affect the battery, since fast charging will reduce the battery's cycle life. This is because the battery converts chemical energy into electrical energy, and charging is a reverse chemical reaction. Frequent fast charging will reduce the battery's recovery ability and reduce the number of charging cycles.
To mitigate the negative effects of fast charging, a crucial component in electric vehicles is the Battery Management System (BMS). For EVs, the BMS is the core component of fast charging. The main function of the BMS is to intelligently manage and maintain each battery cell, preventing overcharging and over-discharging, extending battery life, and monitoring battery status. For example, when fast charging a new energy vehicle, the BMS can control the input current and voltage to minimize damage to the battery. Therefore, this damage is negligible within a limited time, highlighting the importance of the BMS to the battery system. Furthermore, batteries are stored in groups, and during fast charging, some battery packs may not be fully charged under protection conditions. Prolonged fast charging can cause performance degradation in these battery packs.
Experts suggest that after a long period of fast charging, electric vehicles should undergo a slow charge once to extend the life of the car's battery pack.
