Polymer lithium battery: standard voltage 3.7 V, shape more, can be customized, with large capacity, inexpensive, widely used, such as: mobile phones, MP4, portable speakers. The polymer lithium battery is a kind of lithium-ion battery that adopts aluminum-plastic flexible packaging in the structure. It is safer than the battery core of the battery, and it will not cause high-risk security risks when working. Its high power density, smaller thickness, lighter weight, and large capacity, many cell phone batteries are made of polymer batteries. Its internal resistance is small, even less than 35mΩ, which greatly reduces the self-consumption of the battery and makes the power utilization rate higher. In addition, its shape can be customized, according to the appearance of the shell is tailor-made, many appearance of small mobile power is the use of flexible packaging batteries.