What are the safety hazards of fast charging to lithium batteries?
When the lithium-ion battery voltage is higher than 3.0V, it enters the second stage, the high current constant current charging stage (CCFastcharge). Since the lithium-ion battery has been pre-charged in the first stage, its state has been relatively stable (the purpose of the pre-charge stage can be understood in this way~ but it is not rigorous). Therefore, in the second stage, the charging current can be appropriately increased. According to different batteries, the current can vary from 0.1C to several C, where C refers to the battery capacity, such as 2600mAh lithium-ion battery, 0.1C It refers to the current of 260mA.（Lithium - Ion Battery Equipment）
In this charging stage, the standard charging recommended by the state is to charge with 0.1C current, which is the standard charging. However, because the standard charging standard was proposed very early, it was proposed more than ten years ago. At that time, because the lithium-ion battery technology was far less stable than it is now (high current charging is not allowed), there was such a standard~~~ The only advantage of using standard charging is that the charging process is stable, and the probability of explosion is very small; The downside is that it takes time! ! !
Fast charging refers to charging with a current greater than 0.1C at this stage. If the lithium-ion battery capacity is 2600mAh, then the standard charging current is 260mA. As long as the charging current is greater than 260mA, it can mean fast charging. However, from the current level of lithium-ion batteries and the level of charge and discharge management chips, charging with 1C current is no problem. So fast charging is not as dangerous as you think. Generally, the charging current of fast charging is 0.2~0.8C, so fast charging is still safe. Due to the improvement in recent years, the current chargers are basically of the fast charging type. The last stage of the lithium-ion battery charging is the constant voltage charging stage. In this stage, when the lithium-ion battery voltage is detected to be equal to 4.2V, the charger enters the constant voltage charging mode. At this stage, the charging voltage is constant at 4.2V, and the charging current is It is getting smaller and smaller (slowly full, the current will definitely become smaller~). When the charging current is less than 100mA, it is judged that the battery is fully charged and the charging circuit is cut off.
The characteristics of this stage can also explain why after the mobile phone indicates that it is fully charged, unplug the USB cable and go again, and the mobile phone shows that it continues to charge.
In addition, it should be said that the above charging is the most ideal charging process for a single-cell lithium-ion battery, and the current qualified lithium-ion battery charge and discharge protection boards work like this.
There are generally two types of batteries in battery cars: lead-acid batteries and lithium-ion batteries. These batteries are composed of several batteries (lead-acid battery type consists of 6 or 8 series and parallel; lithium-ion battery type consists of several lithium-ion batteries in series and parallel). When it comes to the charging method of the battery pack, there is another big problem here, that is, the problem of battery balancing. Regarding the issue of battery balancing, I won't go into details here, just click on Baidu. I can only say that most of the current battery car batteries do not have battery balancing management, so this leads to the fact that the life of the battery pack is far less than the life of a single battery, which also explains why the battery of the battery car is not durable and will be scrapped in about a year. ~~~At the same time, it also explains that the current predicament of electric vehicle development is the limitation of battery group technology.
In short, the conclusion is: fast charging refers to a charging method with a charging current greater than 0.1C. This charging method has very little impact on the life and stability of a single lithium-ion battery; but if it is a battery car battery pack If so, fast charging is an act of exchanging time for battery life.
The last thing to say is: using the standard charger to charge the battery car is no problem; but for those charging stations that are fully charged in 10 minutes, it is necessary to pay attention, using these charging stations will definitely greatly affect the battery life.
In addition, for battery packs, cell balancing is more important. Fast charging has an impact on the life of the battery pack precisely because the battery pack balance problem has not been resolved.
In this charging stage, the standard charging recommended by the state is to charge with 0.1C current, which is the standard charging. However, because the standard charging standard was proposed very early, it was proposed more than ten years ago. At that time, because the lithium-ion battery technology was far less stable than it is now (high current charging is not allowed), there was such a standard~~~ The only advantage of using standard charging is that the charging process is stable, and the probability of explosion is very small; The downside is that it takes time! ! !
Fast charging refers to charging with a current greater than 0.1C at this stage. If the lithium-ion battery capacity is 2600mAh, then the standard charging current is 260mA. As long as the charging current is greater than 260mA, it can mean fast charging. However, from the current level of lithium-ion batteries and the level of charge and discharge management chips, charging with 1C current is no problem. So fast charging is not as dangerous as you think. Generally, the charging current of fast charging is 0.2~0.8C, so fast charging is still safe. Due to the improvement in recent years, the current chargers are basically of the fast charging type. The last stage of the lithium-ion battery charging is the constant voltage charging stage. In this stage, when the lithium-ion battery voltage is detected to be equal to 4.2V, the charger enters the constant voltage charging mode. At this stage, the charging voltage is constant at 4.2V, and the charging current is It is getting smaller and smaller (slowly full, the current will definitely become smaller~). When the charging current is less than 100mA, it is judged that the battery is fully charged and the charging circuit is cut off.
The characteristics of this stage can also explain why after the mobile phone indicates that it is fully charged, unplug the USB cable and go again, and the mobile phone shows that it continues to charge.
In addition, it should be said that the above charging is the most ideal charging process for a single-cell lithium-ion battery, and the current qualified lithium-ion battery charge and discharge protection boards work like this.
There are generally two types of batteries in battery cars: lead-acid batteries and lithium-ion batteries. These batteries are composed of several batteries (lead-acid battery type consists of 6 or 8 series and parallel; lithium-ion battery type consists of several lithium-ion batteries in series and parallel). When it comes to the charging method of the battery pack, there is another big problem here, that is, the problem of battery balancing. Regarding the issue of battery balancing, I won't go into details here, just click on Baidu. I can only say that most of the current battery car batteries do not have battery balancing management, so this leads to the fact that the life of the battery pack is far less than the life of a single battery, which also explains why the battery of the battery car is not durable and will be scrapped in about a year. ~~~At the same time, it also explains that the current predicament of electric vehicle development is the limitation of battery group technology.
In short, the conclusion is: fast charging refers to a charging method with a charging current greater than 0.1C. This charging method has very little impact on the life and stability of a single lithium-ion battery; but if it is a battery car battery pack If so, fast charging is an act of exchanging time for battery life.
The last thing to say is: using the standard charger to charge the battery car is no problem; but for those charging stations that are fully charged in 10 minutes, it is necessary to pay attention, using these charging stations will definitely greatly affect the battery life.
In addition, for battery packs, cell balancing is more important. Fast charging has an impact on the life of the battery pack precisely because the battery pack balance problem has not been resolved.
