What are the advantages and disadvantages of polymer lithium batteries?

Advantages of polymer lithium battery:

1. The operating voltage of a single battery is as high as 3.6v~3.8v, which is much higher than the 1.2V voltage of NiMH and NiCd batteries.

2. High capacity density, its capacity density is 1.5~2.5 times of Ni-MH battery or Ni-Cd battery, maybe even higher.

3. The self-discharge is small, and the capacity loss is very small after being placed for a long time.

4. Long service life, the cycle life of normal use can reach more than 500 times.

5. No memory effect, no need to empty the remaining power before charging, easy to use.

6. Good safety performance. Polymer lithium battery adopts aluminum-plastic flexible packaging in structure, which is different from the metal shell of liquid battery. Once a safety hazard occurs, liquid battery is easy to explode, while polymer battery will only blow up at most.

7. The thickness is small, can be made thinner, ultra-thin, and the battery can be assembled into a credit card. Generally, liquid lithium batteries adopt the method of customizing the shell first, and then plugging the positive and negative electrode materials. There is a technical bottleneck when the thickness is less than 3.6mm. This problem does not exist for polymer batteries, and the thickness can be less than 1mm, which meets the needs of current mobile phones. direction.

8. Light weight, the battery with polymer electrolyte does not need a metal shell as an outer packaging for maintenance. Polymer batteries are 40% lighter than steel-cased lithium batteries with the same capacity and specifications, and 20% lighter than aluminum-cased batteries.

9. Large capacity, polymer batteries are 10-15% higher than steel shell batteries of the same size and 5-10% higher than aluminum shell batteries, making them the first choice for color screen mobile phones and MMS mobile phones. MMS mobile phones also mostly use polymer batteries.

10. The internal resistance is small. The internal resistance of polymer batteries is smaller than that of ordinary liquid batteries. Now the internal resistance of domestic polymer batteries can even be below 35mΩ, which greatly reduces the self-consumption of batteries and extends the life of mobile phones. The standby time can fully meet the international standards. This kind of polymer lithium battery that supports large discharge current is an ideal choice for remote control models, and has become the most promising product to replace NiMH batteries.

11. The shape can be customized, and the manufacturer does not have to be limited to the standard shape, and can economically make the appropriate size. Polymer batteries can increase or decrease the thickness of the battery cell according to the needs of customers, and develop new battery cell models. The price is cheap and the mold opening cycle is short. 

12. Excellent discharge characteristics. Polymer batteries use colloidal electrolytes. Compared with liquid electrolytes, colloidal electrolytes have stable discharge characteristics and higher discharge channels.

13. The design of the protection board is simple. Due to the use of polymer materials, the battery cells will not catch fire or explode, and the battery cells themselves have sufficient safety. Therefore, the protection circuit design of polymer batteries can consider omitting PTC and fuses, thereby saving battery costs. 

Defects of polymer lithium batteries:

1. The cost of the battery is high, and the purification of the electrolyte system is difficult.

2. It is necessary to protect the circuit control. Overcharging or overdischarging will damage the reversibility of the chemical substances inside the battery, which will seriously affect the life of the battery.