How to judge the quality of lithium iron phosphate battery combination

Consistency: If the lithium battery pack with poor consistency has a protection board, its capacity will be the lowest according to the bucket principle, which will cause the entire battery pack to not fully discharge power due to one battery core. The ground absorbs electrical energy, and over time, the life of the battery pack is short. If the battery pack does not have a protective plate, there is not only a loss of capacity, but also a safety problem that may cause overheating and explosion.

The method of testing consistency is to connect the batteries that need to be tested in series, 4 groups or 6 groups, to do 1C charging and 3C discharging. During the charging and discharging process, it is enough to see the difference in voltage rise and fall of the battery.

Self-discharge rate: Since lithium iron phosphate battery packs are often used for power lithium batteries, the power consumption is large, which requires that the self-discharge rate of the battery pack should be less than 2% per month. To achieve this, the above consistency requirements must not be met. Less, after the consistency test is passed, the self-discharge rate is detected by charging a battery of equal capacity, standing for one month, and measuring the capacitance value.

High magnification: The battery pack that can withstand high-rate charge and discharge has a strong ability to charge and discharge quickly. For lithium iron phosphate batteries, it must be able to charge and discharge quickly to meet the requirements for power lithium batteries. The test method for high magnification is: according to the conditions provided by the manufacturer of the lithium battery, the highest rate is tested. If there is a serious problem of heat generation during charging and discharging, the quality of the battery is not good. In general, the power lithium battery pack should meet the safety requirements of 3C charging and 30C discharge.

Long life: As a general requirement, lithium iron phosphate batteries have 85% capacity after 2000 C discharges and 80% capacity after 3000 cycles. Of course, each manufacturer because craft level and material are different, the standard that make is different. The testing method is theoretically based on the data provided by the manufacturer. Whether the data provided by the manufacturer is true or not can only be determined by the brand effect at present, which depends on which brand the consumers believe.

1: Connect the lithium iron phosphate battery correctly to the tester fixture

2: Edit the charging and discharging process steps and start testing.

3: After the test is completed, import the data to the desktop for editing.

4: Analyze the data one by one.

lithium iron phosphate battery charge and discharge curve

5: The constant current/constant voltage (cc/cv) charging time ratio is approximately 3/1.

6: After discharge, the voltage rises faster and higher.

7: The working voltage area is too small.

Precautions

The above was charged and discharged according to 1c, and the time was set to 5 min.

The test fixture should be clean, otherwise sampling will be inaccurate.

The battery access fixture should be correct, positive and negative.

How to test the quality of lithium batteries:

1. The fastest test method is to test the internal resistance and the maximum discharge current. The lithium battery with good quality has very small internal resistance and the maximum discharge current is very large. Using a 20A range multimeter, directly shorting the two electrodes of the lithium battery, the current should generally be around 10A, or even higher, and can maintain a period of time, relatively stable is a good battery.

2. Look at the appearance. The fullness of the appearance, such as a lithium battery of about 2000mAh, is relatively large. Workmanship is more elaborate or the packaging is full.

3. Look at the hardness. The middle part of the lithium battery can be lightly pinched by hand or moderately squeezed. The hardness is moderate, and no soft squeeze feels that the lithium battery is a relatively high quality battery.

4. Look at the weight. Remove the outer packaging to see if the weight of the battery is relatively heavy, if the thick is a high-quality battery.

5. In the lithium battery live working process, continuous discharge for about 10 minutes, if the battery poles are not hot, it proves that the battery protection board system is perfect. Generally the quality of the lithium battery with high quality protection board is better than the ordinary lithium battery.

The page contains the contents of the machine translation.