How to judge the quality of lithium iron batteries?

To judge the quality of lithium iron batteries, the most basic analysis can be from the following points: 1. Uniformity The most difficult thing to do with batteries is uniformity, but the most important thing for battery pack strings is uniformity. If 10 batteries are stringed together, one of them reaches the over-discharge protection standard first, and the other several have sufficient power, will the usable capacity of this string of battery packs be reduced as a whole? The same is true for having a first over-discharge. A battery pack with insufficient uniformity will easily break if there is no protection board, and it is easy to overcharge or over discharge; a battery pack with a protection board, the available capacity will be lower as it is used. This is also the reason why many battery cell factories have processed batteries but are afraid to launch products that require stringing. Because to achieve uniformity, the control of the entire process must be very strict. Simple test method: connect 4 cells in series, do 1C charge and 3C discharge, and observe the voltage of each cell during the charging and discharging process, and see the difference of the rise and fall. It would be better if you can do it continuously for 4 or 5 times. 2. Self-discharge rate The theoretical value of the self-discharge rate of lithium iron battery should be less than 2% per month. If it exceeds this value, it is not a good battery. There is either a problem with the manufacturing process or a problem with the materials used. Low self-discharge rate is inherently a characteristic of lithium iron batteries. If the self-discharge rate is high, when you install the finished product and send it to the customer, the battery is out of power. How will the customer feel? Furthermore, it also means that a lot of electrical energy is wasted. In terms of strings, it will affect the balance of the battery pack, that is to say, the available electric capacity of the battery pack will become less and less, and the life of the battery pack will be much reduced. Simple test method: Take 10 batteries with approximately the same capacity and let them stand for one month after fully charged, and then measure the capacity value to calculate its self-discharge rate. (Remember to measure the voltage before and after standing, and compare the changes in battery voltage.) 3. ChargeC-rate (ChargeC-rate) is one of the most advantageous features of lithium iron batteries. Fast charging and discharging make its characteristics very similar to super capacitors, but its capacitance is hundreds of times larger than super capacitors. If its fast charging and discharging characteristics are insufficient, the use of lithium iron batteries is of little significance. Generally speaking, a good-quality lithium-iron battery can charge up to 3C (about 20 minutes full charge), and the discharge rate can reach 30C. Higher charging and discharging rates can be achieved if there are special requirements. The above situation is on the premise that the battery life cannot be damaged. Simple test method: that is, the highest charge-discharge rate can be used to test the specifications provided by the manufacturer; if the battery core heats up severely during the test, the quality of the battery core is not very good. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete it.