Lithium iron phosphate batteries have been widely used because of their high safety, long cycle life, and large capacity. Various products of lithium iron phosphate batteries are also commonly used in our daily lives.
Although the lithium iron phosphate battery has a greater safety performance compared to other batteries, it is based on the condition that we use it in the correct way. If we use the wrong method to use lithium battery products, such as using the wrong method and technique to charge the lithium iron phosphate battery, this is a dangerous behavior.
Therefore, this time, the editor of Cuneng Electric will introduce some methods and techniques for charging lithium iron phosphate batteries. I hope it will be helpful to everyone.
Before introducing charging methods and techniques, it is necessary to understand the structure and working principle of lithium iron phosphate batteries.
The structure and working principle of lithium iron phosphate battery
"Lithium iron phosphate battery" refers to a lithium ion battery that uses lithium iron phosphate as the positive electrode material.
As the positive electrode of the battery, lithium iron phosphate is connected to the positive electrode of the battery by an aluminum foil, and a polymer separator is in the middle, which separates the positive electrode from the negative electrode, but lithium ions can pass through but electrons cannot pass. The negative electrode of the battery is composed of carbon (graphite). The copper foil is connected to the negative electrode of the battery. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.
When charging a lithium iron phosphate battery, the lithium ions in the positive electrode migrate to the negative electrode through the polymer separator; during the discharge process, the lithium ions in the negative electrode migrate to the positive electrode through the separator.
Lithium iron phosphate battery charging methods and techniques
New battery activation
Because the lithium iron phosphate battery may have been placed in the warehouse for a period of time before it reaches the user, and the battery will enter the dormant state after being placed for a period of time, it needs to be activated at this time. The battery can be activated as long as 3-5 normal charge and discharge cycles are performed.
Due to the characteristics of the lithium battery itself, it is determined that it has almost no memory effect. Therefore, the user does not need special methods and equipment during the activation process of the new lithium battery. It is best to use the standard method of charging from the beginning, this "natural activation" method.
Usually charging
Before charging starts, the charger will supply the battery with a small current, and at the same time detect the battery voltage change, and gradually increase the current until the set value. This process can be regarded as an activation or test charge.
The charger charges the battery with a constant current. As the battery voltage increases, the charger increases the charging voltage at the same time to speed up the charging speed.
When the battery reaches the 4.2V cut-off voltage, the battery only charges about 70% (not full) at this time. At this time, the charger continues to charge the battery with a constant voltage and a gradually decreasing current, until the value is less than 0.1A and the battery voltage continues to rise when the battery voltage continues to rise before stopping charging.
When charging lithium iron phosphate batteries and related products, the charger is best to choose the original special charger. Because the original charger is the most suitable for voltage, charging speed, etc., it is also the least damage to the battery.
