Recently, Xiaomi announced its 200W fast charging technology, which can fully charge a 4000mAh battery in just 8 minutes.
The fact is, fast charging is a key area of market focus not only in the mobile phone sector but also in the power battery sector.
Generally speaking, most electric vehicles use conventional charging technology, which takes 8-10 hours to charge. Fast charging, on the other hand, can fully charge the battery in just 1 hour.
To simplify the concept, fast charging actually uses high-current, high-power direct current to charge the battery. The real principle is that in fast charging mode, lithium ions in the lithium battery move at high speed and are instantly embedded into the two electrodes of the battery.
The method involves first charging the battery with a wider charging pulse to increase the terminal voltage of the lithium battery. When the charging time limit set by the charging system is reached, the charging system cuts off the power supply current to stop the battery from charging. Then, when another charging point is reached intermittently, the charging is restarted. This process is repeated until all the lithium ions inside the battery gather at the positive and negative electrodes, and the battery is quickly fully charged.
This fast charging technology places high demands on the battery itself. The battery must have an automatic management system, as well as very reliable thermal stability and the ability to withstand high voltage and high current.
The above are the battery requirements for achieving fast charging. In order to achieve this kind of fast charging, a matching charging system is also required. Now, many cities provide fast charging piles with a power of up to 20KW and above, which can convert 10KV high-voltage AC power into hundreds of amps of DC power and continuously transmit it into the car battery system through a dedicated cable.
Given that current battery pack balancing technology, power transmission and distribution technology, and especially heat dissipation technology are not yet up to par, true fast charging cannot be fully realized. However, it has significantly shortened charging time compared to ordinary charging technology. Most importantly, as can be seen from the principle, fast charging will not severely damage the battery or sacrifice its lifespan as commonly believed.
