li-ion 18650 battery

　　li-ion 18650 battery fast charging technical issues, what risks does li-ion 18650 battery fast charging bring?

　　li-ion 18650 battery fast charging technical issues, what risks does li-ion 18650 battery fast charging bring? In the absence of a better alternative, fast charging has become a temporary solution. Generally, fast charging is high-power DC charging, which can fully charge 80% of the battery capacity in half an hour. The voltage of fast charging DC charging is generally greater than the battery voltage. So regarding the technical issues of li-ion 18650 battery fast charging, what are the risks of li-ion 18650 battery fast charging? The editor is here to clear up your doubts!

　　li-ion 18650 battery fast charging technical issues, what risks does li-ion 18650 battery fast charging bring?

　　The three basic ways to realize fast charging of mobile phones are: the voltage remains unchanged and the current is increased; the current remains unchanged and the voltage is increased; both voltage and current are increased. But to truly achieve fast charging, it is not just about increasing the current and battery. Fast charging technology is a complete system, including fast charging adapters and intelligent power management systems.

　　Long-term fast charging affects the life of lithium batteries. Fast charging of lithium batteries is at the expense of the cycle life of the battery, because the battery is a device that generates electrical energy through electrochemical reactions. Charging is a reverse chemical reaction, and fast charging will instantly A large current is input into the battery and frequent use of fast charging mode will reduce the battery's recovery ability and reduce the number of battery charge and discharge cycles.

　　What are the risks of fast charging of lithium batteries?

　　Fast charging of lithium batteries brings three effects: thermal effect, lithium precipitation and mechanical effect

　　1. Frequent fast charging accelerates the polarization of battery cells.

　　When the continuous charging current is large, the ion concentration at the electrode increases, the polarization intensifies, and the battery terminal voltage cannot directly correspond to the charged power/energy in linear proportion. At the same time, when charging with a large current, the increase in internal resistance will cause the Joule heating effect to intensify and bring about side reactions, such as reaction decomposition of the electrolyte, gas production, and a series of other problems. The risk factor suddenly increases, which affects the safety of the battery. Non-power batteries Life span will inevitably be significantly shortened.

　　2. Frequent fast charging may cause the battery core to crystallize.

　　Fast charging of lithium batteries means that lithium ions quickly escape and "swim" to the negative electrode. At this time, the negative electrode material needs to have the ability to quickly insert lithium. Since the potential of lithium insertion is similar to the potential of lithium precipitation, under fast charging or low temperature conditions, lithium Ions may precipitate on the surface to form dendrites of lithium. Dendritic lithium will pierce the separator, causing secondary loss of Li and reducing battery capacity. When the lithium crystal reaches a certain amount, it will grow from the negative electrode to the separator, causing the risk of battery short circuit.

　　3. Frequent fast charging will shorten battery life

　　Frequent charging can also easily accelerate the consumption of battery life, and even lead to problems such as reduced battery activity and shortened battery life. Especially after the addition of fast charging technology, although the charging speed is very fast in the early stage, unplugging the battery before it is fully charged to 100% will cause multiple charging and increase the number of battery cycles. Long-term use will reduce the battery life. activity, thereby accelerating the aging of the battery.

　　High temperature is the biggest killer of li-ion 18650 battery aging. The high power of fast charging will heat up the battery in a short time. Although non-fast charging has low power and low heat per unit time, it requires a longer power-on time. In this way, battery heat will also accumulate over time, and the difference in heat generated during the charging process is not enough to cause a difference in the battery aging rate.

　　Based on the above, we can conclude that fast charging has high requirements on battery quality, will cause a great loss to the battery life, and the safety factor will be significantly reduced, so do it as little as possible when it is not necessary. Frequent fast charging of the battery will cause damage to the battery, but due to differences in battery cell density, materials, ambient temperature and battery management systems, the degree of damage to the battery during the fast charging process is also different.

　　At present, most batteries will design a reasonable charging strategy based on the remaining power of the battery, battery performance and other factors, and try to minimize the damage to the battery by fast charging by adjusting the charging power. Therefore, users who occasionally use fast charging do not have to worry too much about damaging the battery!

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