Lithium batteries are batteries that use lithium metal or lithium alloy as the negative electrode material and use non aqueous electrolyte solutions, hence they are also known as lithium metal batteries. Unlike other batteries, lithium batteries have the characteristics of high charging density, long lifespan, and high unit cost. Depending on the structural design and electrode materials, lithium batteries can generate voltages ranging from 1.5 V (equivalent to zinc carbon or alkaline batteries) to 3.7 V. Next, BAIJIAN will explain in detail what are the testing standards for lithium batteries and what are the testing methods for lithium batteries 1. What are the testing standards for lithium batteries? 1. In terms of discharge performance testing, the standard requires charging and discharging at the specified charging and discharging rate at (20 ± 5) ℃ to the termination voltage, with a discharge time not less than the specified value. 2. High temperature and low temperature performance were tested at (55 ± 2) ℃ and (-20 ± 2) ℃ respectively [-10 ± 2) ℃ for polymer lithium-ion batteries]. After the experiment, the battery was removed and left to stand at an ambient temperature of (20 ± 5) ℃ for 2 hours. The appearance of the battery should be free from deformation and cracking. 3. The requirement for cycle life is to charge and discharge at 1C * * at an ambient temperature of (20 ± 5) ℃ until the termination voltage is reached. After being left for 0.5-1h, the next cycle of charge and discharge is carried out until the two consecutive discharge times are less than 36min. The cycle life of the battery should be no less than 300 times. 4. For overcharging, over discharge, and short circuit protection, it is required that the battery does not explode, catch fire, smoke, or leak under specified operating conditions 2. What are the testing methods for lithium batteries? 1. Self discharge testing generally uses 24-hour self discharge to quickly test its charge retention ability. The battery is discharged at 0.2C to 3.0V, charged at constant current and constant voltage 1C to 4.2V, with a cut-off current of 10mA. After 15 minutes of storage, the discharge capacity C1 is measured at 1C to 3.0V, and then charged at constant current and constant voltage 1C to 4.2V, with a cut-off current of 100mA. After 24 hours of storage, the 1C capacity C2, C2/C1 are measured × 100% should be greater than 99%. 2. Internal resistance measurement: The internal resistance of a battery refers to the resistance experienced by the current flowing through the battery during operation. It is generally divided into AC internal resistance and DC internal resistance. Due to the small internal resistance of a rechargeable battery, when measuring DC internal resistance, the actual value cannot be measured due to the polarization of the electrode, which generates polarization internal resistance; Measuring its AC internal resistance can eliminate the influence of polarization internal resistance and obtain the true internal value. The AC internal resistance testing method is to use the characteristic that the battery is equivalent to an active resistor, give the battery a constant current of 1000HZ and 50mA, sample its voltage, rectify and filter it, and perform a series of processing to accurately measure its resistance value. 3. IEC standard cycle life test IEC stipulates that the standard cycle life test for lithium batteries is: after the battery is discharged at 0.2C to 3.0V/cell, it is charged at 1C constant current and voltage to 4.2V, with a cut-off current of 20MA. After being left for 1 hour, it is discharged at 0.2C to 3.0V (one cycle) for 500 cycles, and the capacity should be above 60% of the initial capacity. 4. Internal pressure test for lithium batteries: (UL standard) Simulate whether the battery is leaking or bulging at an altitude of 15240m (low pressure of 11.6kPa). Specific steps: Charge the battery 1C with constant current and voltage to 4.2V, cut-off current of 10mA, and then store it in a low-pressure box with a pressure of 11.6Kpa and a temperature of (20 ± 3 ℃) for 6 hours. The battery will not explode, catch fire, crack, or leak. 5. Drop test: After fully charged, the battery pack is dropped from three different directions at a height of 1m onto a hard rubber plate, twice in each direction. The battery pack's electrical performance should be normal, and the outer packaging should not be damaged