This article outlines six methods to assess the quality of lithium batteries: inspecting exterior and packaging, detecting capacity, evaluating voltage stability, investigating charging and discharging performance, and verifying safety performance. Following these steps can help determine if a lithium battery meets quality standards, but it requires professional electrical expertise.
1. Check the exterior and packaging
Shell condition: Carefully inspect the shell of the lithium battery, the shell of a high-quality lithium battery should be flat and smooth, without obvious scratches, bumps, deformation or bulging. If there is a bulge, it is likely that there will be a problem with the internal battery, which will affect the performance and safety of the battery, and it is likely that it will not meet the due quality standards.
Identification integrity: Check the battery surface identification, such as brand, model, rated voltage, rated capacity, production date, implementation standards and other information should be clearly and accurately marked. For example, if the rated capacity is not clearly labeled or does not match the value advertised by the seller, then it is necessary to doubt whether the quality is up to standard. At the same time, the packaging should also be formal, including the necessary instructions for use, precautions and relevant certification marks, etc., if the packaging is poor and lacks key information, the quality may be worrying.
2. Detect capacity
Professional instrument measurement: With the help of a professional battery capacity tester, the battery is fully charged first, and then the actual amount of power discharged is recorded according to the standard discharge process. Generally speaking, there is a reasonable error between the actual capacity and the rated capacity promised by the seller, such as within ±5% for the common one. If the deviation exceeds this range, such as the seller promised 3000mAh capacity, but the actual test is only about 2500mAh, then it can basically be judged that the quality standard is not met.
Actual use comparison: apply the lithium battery to the corresponding device, and estimate it based on past experience or the battery life of the device under normal use. For example, if it is used for a certain electric toothbrush, the battery that normally meets the standard can be used for about 30 days, and the newly purchased battery will run out of power after less than 20 days, then it is likely that its capacity is not up to standard and there is a problem with the quality.
3. Evaluate voltage stability
Load test: Connect a suitable load device and use a multimeter and other tools to monitor the voltage change in real time during the battery discharge process. When the lithium battery with high quality is discharged, the voltage will drop relatively smoothly, and there will be no high and low and large fluctuations in the normal use range. For example, if the voltage fluctuates frequently in excess of 0.5V during discharge, or the voltage drops much faster than normal, the voltage stability of the battery is not good and does not meet the quality requirements.
Comparison reference method: if there is a condition to obtain a lithium battery of the same specification and reliable quality, the discharge test is carried out at the same time under the same load and environment, and the voltage change curves of the two are compared. If the voltage curve of the purchased lithium battery is significantly more unstable and fluctuates greatly, it means that it does not meet the due quality standards in terms of voltage stability.
4. Investigate the charging and discharging performance
Charging performance: Use the matching charger to charge the battery as required, under normal circumstances, it should be able to be fully charged smoothly within the specified time, and the battery will not appear abnormal heating, smoke and other phenomena during the charging process. For example, if a lithium battery normally takes 2 hours to charge, but the newly purchased one takes 3 hours to recharge, or the shell is severely hot during charging, it indicates that its charging performance is problematic and does not meet quality standards.
Discharge performance: When using battery discharge in equipment, in addition to paying attention to capacity and voltage stability, it is also necessary to pay attention to whether there is a power failure in the middle of the process, and the discharge speed is abnormally fast. For example, in the use of power tools, the discharge is often interrupted for no reason, and the equipment needs to be restarted before it can continue to be used, which reflects the poor discharge performance of the battery and does not meet the qualified quality standards.
5. Verify safety performance
Overcharge and over-discharge test (cautious operation): In the case of professional protection measures and professional guidance, a small-scale overcharge and over-discharge test can be carried out to observe whether the battery has dangerous conditions such as bulging, leakage, smoke or even fire and explosion. Lithium batteries that meet the quality standards usually have a perfect protection mechanism, which can effectively avoid the occurrence of such extreme dangerous situations, and if the above undesirable phenomena occur, they obviously do not meet the quality standards. However, this test is dangerous, and it is not recommended to operate it yourself without professional conditions, and you can refer to the relevant safety certification.
6. Conclusion
According to above method we can basically know the quality standard of the lithium battery that you buy, but we must make sure we have the professional electrical person to handle all the process.
