What are the items for lithium battery performance testing

At the beginning of the design of the lithium battery product, the performance test of the selected lithium battery model will be carried out simultaneously. The performance and reliability of the lithium battery have a direct impact on the terminal product. Therefore, the performance test of the lithium battery can troubleshoot the problem at an early stage. And solve, then what are the items of lithium battery performance test; what are the items of lithium battery performance test; 1. Self-discharge test The self-discharge test of lithium battery is: generally 24-hour self-discharge is used to quickly test its charge retention capacity, Discharge the battery to 3.0V at 0.2C, charge to 4.2V at 1C at constant current and constant voltage, cut-off current: 10mA, after 15 minutes of standing, discharge at 1C to 3.0V to measure its discharge capacity C1, and then charge the battery at constant current and constant voltage to 1C Charge it to 4.2V, cut-off current 100mA, and measure 1C capacity C2 after being left for 24 hours. C2/C1×100% should be greater than 99%. Second, internal resistance measurement The internal resistance of a lithium battery refers to the resistance that the current flows through the battery when the battery is working. It is generally divided into AC internal resistance and DC internal resistance. Since the internal resistance of the rechargeable battery is very small, the DC internal resistance is measured At this time, because the electrode is easily polarized and produces a polarized internal resistance, its true value cannot be measured; and the AC internal resistance can be measured to avoid the influence of the polarized internal resistance, and the true internal value can be obtained. The AC internal resistance test method is: Utilizing the characteristics of a lithium battery equivalent to an active resistor, give the battery a constant current of 1000HZ, 50mA, and a series of processing such as voltage sampling, rectification and filtering to accurately measure its resistance. 3. Internal pressure test The internal pressure test of the lithium battery is: (UL standard) The simulated battery is tested at an altitude of 15240m (low air pressure 11.6kPa) to check whether the lithium battery leaks or bulges. Specific steps: Charge the battery with 1C constant current and constant voltage to 4.2V, cut-off current 10mA, and then store it in a low-pressure box with an air pressure of 11.6Kpa and a temperature of (20±3°C) for 6 hours, the battery will not explode , Fire, cracks, leakage. Fourth, the impact test After the lithium battery is fully charged, place a 15.8mm diameter hard rod on the battery, and use a 20-pound weight to drop from a height of 610mm on the hard rod. The battery should not explode and catch fire. Or leakage. 5. Lithium battery cycle life test The cycle life test mainly checks the charge and discharge times of the lithium ion battery when the available capacity drops to the allowable value. The specific steps are as follows: ①The lithium ion battery is discharged at a constant current of 0.2C to the specified termination voltage (generally 3.0V) at an ambient temperature of (20±5) ℃, and then charged to the termination voltage at a constant current of 0.2C. (Generally 4.2V), switch to constant voltage charging (the charge termination current is generally 0.02C); ②Lithium batteries should be discharged to the specified discharge termination voltage at a constant current of 0.2C at an ambient temperature of (20±5)℃ ③Lithium-ion batteries should be cycled at an ambient temperature of (20±5)℃, and the batteries should be stored for no more than 1h between charging and discharging or between discharging and charging; Charge until the discharge capacity is less than 70% of the rated capacity. How to check the quality of lithium batteries? 1. The fastest inspection method is to test the internal resistance and the maximum discharge current. A good quality lithium battery has a very small internal resistance and a large maximum discharge current. Use a multimeter with a 20A range to directly short the two electrodes of the lithium battery. The current should generally be about 10A, or even higher, and it can be maintained for a period of time. A relatively stable battery 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. The workmanship is more delicate or the packaging is more plump. 3. Look at the hardness. The middle part of the lithium battery can be squeezed lightly or moderately with the hand. The hardness is moderate, and there is no soft squeezing feeling, which proves that the lithium battery is a relatively high-quality battery. 4. Look at the weight. Remove the outer packaging and feel whether the weight of the lithium battery is heavy. If it is heavy, it is a high-quality battery. 5. During the live working process of the lithium battery, continue discharging 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 lithium batteries with high-quality protection boards is better than ordinary lithium batteries. Since its introduction, lithium batteries have quickly become a leader in the battery field with their excellent performance. However, with the gradual expansion of its application range and the increasing volumetric energy density of a single battery, the capacity of lithium batteries is increasing. Security is also getting more and more attention. Therefore, performance testing and inspection are still necessary. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: What is the difference between UPS power supply and EPS power supply