Polymer electrolyte lithium battery

The positive and negative electrode materials used in polymer electrolyte lithium batteries are the same as liquid lithium, 

and the working principle of the battery is basically the same. 

Their main difference lies in the electrolyte. Lithium batteries use liquid electrolytes, while polymer lithium batteries use solid polymer electrolytes instead. 

These polymers can be in a "dry" or "gel" state, and currently most use polymer gel electrolytes.

Polymer electrolyte lithium batteries can be divided into three categories:

1、Solid polymer electrolyte lithium battery.

The electrolyte is a mixture of polymer and salt, and this type of battery has low ion conductivity at room temperature, making it suitable for high-temperature use.

2、 Gel polymer electrolyte lithium battery.

Adding plasticizers and other additives to solid polymer electrolytes can improve ion conductivity and enable the battery to be used at room temperature.

3、 Lithium batteries using polymer cathode materials. Using conductive polymer as the positive electrode material,

 its energy is three times that of existing lithium batteries, making it the latest generation of lithium batteries. 

Due to the use of solid electrolytes instead of liquid electrolytes, polymer lithium batteries have advantages such as thinning, 

arbitrary area and shape compared to liquid lithium batteries, and do not have safety issues such as leakage, combustion and explosion. 

Therefore, aluminum-plastic composite films can be used to manufacture battery casings, thereby increasing the capacity of the entire battery; 

Polymer lithium batteries can also use polymers as positive electrode materials,

 which will increase their mass to energy ratio by more than 50% compared to current liquid lithium batteries. 

In addition, polymer lithium batteries have improved working voltage and charge discharge cycle life compared to lithium batteries.

Advantages of lithium polymer batteries:

1. Good safety performance

Polymer lithium batteries use aluminum-plastic flexible packaging in their structure, which is different from the metal casing of liquid batteries. In the event of a safety hazard, liquid batteries are prone to explosion, while polymer batteries can only inflate at most.

2. Small thickness, can be made thinner

Ordinary liquid lithium batteries adopt the method of customizing the shell first, and then inserting positive and negative electrode materials. There is a technical bottleneck in achieving a thickness of less than 3.6mm, while polymer batteries do not have this problem. The thickness can be reduced to less than 1mm, which meets the current demand for mobile phones.

3. Lightweight

Polymer batteries are 40% lighter than steel shell lithium batteries of the same capacity specification and 20% lighter than aluminum shell batteries.

4. Large capacity

Polymer batteries have a capacity 10-15% higher than steel shell batteries of the same size and specifications, 

and 5-10% higher than aluminum shell batteries, making them the preferred choice for color screen phones and MMS phones.

 Currently, most newly released color screen and MMS phones on the market also use polymer batteries.

5. Low internal resistance

The internal resistance of polymer battery cells is smaller than that of general liquid battery cells. 

Currently, the internal resistance of domestic polymer battery cells can even reach below 35m Ω, 

greatly reducing the self consumption of batteries and extending the standby time of mobile phones, 

which can fully reach the level of international standards. 

This polymer lithium battery that supports high discharge current is an ideal choice for remote control models and has become the most promising alternative to nickel hydrogen batteries.

6. Customizable shape

Polymer batteries can increase or decrease the thickness of battery cells according to customer needs, develop new battery cell models, be inexpensive, have short mold cycles, 

and some can even be customized according to the shape of the phone to fully utilize the space of the battery casing and increase battery capacity.

7. Excellent discharge characteristics

Polymer batteries use colloidal electrolytes, which have smooth discharge characteristics and higher discharge platforms compared to liquid electrolytes.

8. The design of the protective board is simple

Due to the use of polymer materials, the battery cells do not ignite or explode, and have sufficient safety. 

Therefore, the protection circuit design of polymer batteries can consider omitting PTC and fuses to save battery costs. 

Polymer lithium batteries have great advantages in terms of safety, volume, weight, capacity, and discharge performance.