Lithium ion batteries can be divided into liquid lithium-ion batteries and polymer lithium-ion batteries. The positive and negative electrode materials used in the polymer are the same as those of liquid lithium ion, and the working principle of the battery is basically the same.
The main difference between them lies in the different electrolytes. Lithium ion batteries use liquid electrolytes, while polymer lithium ion batteries use solid polymer electrolytes instead. This kind of polymer can be "dry" or "colloidal". At present, most of them use polymer colloidal electrolytes. We usually call polymer lithium batteries polymer batteries, Lithium ion batteries are called lithium batteries.
The capacity density of polymer battery is 1.5 ~ 2.5 times or higher than that of Ni MH battery or Ni Cd battery. The thickness is small, and it can be made thinner. Ordinary liquid lithium battery adopts the method of customizing the shell first, and then plugging the positive and negative materials. The thickness of polymer battery is less than 3.6 mm, which has a technical bottleneck. The polymer cell does not have this problem, and the thickness can be less than 1 mm, which is in line with the current demand direction of ultra-thin mobile phones.
The working voltage of single polymer battery is 3.6V ~ 3.8V, which is much higher than that of Ni MH and Ni Cd battery. The polymer battery is 40% lighter than the steel shell lithium battery of the same capacity and 20% lighter than the aluminum shell battery. The capacity of polymer battery is 10-15% higher than that of steel shell battery and 5-10% higher than that of aluminum shell battery.
The self discharge of polymer battery is small, and the capacity loss of polymer battery is small after a long time. The shape of polymer battery can be customized, and the manufacturer does not need to be limited to the standard shape, so it can be made into the right size economically. Polymer battery can increase or decrease cell thickness according to customer's demand, and develop new cell models with low price and short mold opening cycle. Some can even be customized according to the shape of mobile phone, so as to make full use of space and improve battery capacity.
Compared with liquid electrolyte, colloidal electrolyte has stable discharge characteristics and higher discharge platform.
The design of polymer battery protection board is simple. Due to the use of polymer materials, the cell does not catch fire or explode, and the cell itself has enough safety. The cycle life of polymer battery can reach more than 500 times. There is no memory effect, and it is not necessary to empty the remaining power before charging. The polymer battery is easy to use, and it does not need to be continuously charged for several hours to "activate" before use. It has good safety performance. Polymer lithium-ion battery adopts aluminum plastic flexible packaging in structure, which is different from the metal shell of liquid cell. In case of potential safety hazard, liquid cell is easy to explode, while polymer cell will only blow up at most.