One of the fastest ways to check the quality of lithium-ion batteries is to test their internal resistance and maximum discharge current. A high-quality lithium-ion battery has a very small internal resistance and a high discharge current. Use the two electrodes of a multimeter directly connected to a lithium-ion battery. The current should usually be within a certain value, or even higher. A lithium-ion battery that can maintain relative stability for a period of time. Observing the exquisite and tidy appearance of lithium-ion batteries can still provide some feedback on their quality and workmanship. The overall appearance must be neat, and the same applies to lithium-ion batteries. Because lithium-ion batteries want to ensure their own safety and quality, only by manufacturing sophisticated equipment can they ensure that quality issues do not occur during the production process. The hardness of lithium-ion batteries can be checked by pinching or pressing the middle part of the battery with hands or tools. If the hardness of lithium-ion batteries is moderate, the soft squeezing feeling proves that the battery cells of lithium-ion batteries are relatively high-quality. Perceived weight: In addition to the packaging of lithium-ion batteries, perceive whether the weight of the battery is relatively heavy. If its weight has a certain thickness, it belongs to high-quality battery cells. During the continuous discharge observation of lithium-ion battery power operation, discharge continuously for about ten minutes. If the electrodes of lithium-ion batteries are not hot, it proves that the protection system of lithium-ion batteries is relatively complete. Under normal circumstances, the quality of lithium-ion batteries with high-quality battery protection systems will not be too poor