How to distinguish the quality of lithium iron phosphate battery packs?
March 9, 2021
How to distinguish the quality of lithium iron phosphate battery packs?
1. Consistency
If a lithium-ion battery pack with poor consistency has a protective plate, according to the bucket principle, its capacity will be the lowest, so that the entire battery pack will not be able to fully release or absorb energy due to one cell. Electricity, over time, the life of the battery pack is short. If the battery pack is not equipped with a protective plate, not only will there be a loss of capacity, but there may also be safety issues and overheating and explosions.
The method of testing consistency is to connect the cells to be tested in series, 4 in a group or 6 in a group, and do 1C charging and 3C discharging. During the charging and discharging process, just look at the difference in the rise and fall of the cell voltage.
2. Self-discharge rate
Due to the large power consumption of lithium iron phosphate battery packs, the self-discharge rate of the battery pack should be less than 2% per month. To achieve this, the above-mentioned consistency requirements are indispensable. After the consistency test is qualified, the self-discharge rate should be less than 2%. The method of detecting the discharge rate is to charge the battery with the same capacity and let it stand for one month, and then measure its capacity value.
3. High magnification
A battery pack that can withstand high-rate charge and discharge has a strong ability to charge and discharge quickly. For lithium iron phosphate batteries, they must be able to charge and discharge quickly to meet their requirements for lithium-ion batteries.
The test method for high rate is: use the highest rate test according to the conditions supplied by the lithium-ion battery UPS manufacturer. If there is an obvious serious heating problem during the charging and discharging process, the quality of the battery is not good. Generally speaking, the power lithium-ion battery pack should meet the safety requirements of 3C charging and 30C discharging.
4. Long life: As a general requirement, the lithium iron phosphate battery pack has 85% capacity after 2000 discharges at 1C, and 80% capacity after 3000 discharges. Of course, each manufacturer has different standards due to different technological levels and materials.