Advantages and disadvantages of polymer lithium batteries

Advantages of polymer lithium battery:

1. The operating voltage of a single cell 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, which is 1.5~2.5 times or even higher than that of NiMH batteries or NiCd batteries.

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

4. Long service life, under normal use, its cycle life can reach more than 500 times.

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

6. Good safety performance

The polymer lithium battery uses aluminum-plastic soft packaging in its structure, which is different from the metal shell of liquid batteries. Once a safety hazard occurs, the liquid battery is prone to explosion, while the polymer battery will only bulge at most.

7. Small thickness, can be made thinner

Ultra-thin, the battery can be assembled into a credit card. Ordinary liquid lithium batteries use the method of first customizing the shell and then inserting the positive and negative electrode materials. There is a technical bottleneck in achieving a thickness below 3.6mm, but polymer batteries do not have this problem and the thickness can be less than 1mm, which meets the current demand for mobile phones.

8. Lightweight

Batteries using polymer electrolytes do not need metal shells as protective outer packaging. Polymer batteries are 40% lighter than steel-shell lithium batteries of the same capacity and 20% lighter than aluminum-shell batteries.

9.Large capacity

The capacity of polymer batteries is 10-15% higher than that of steel-shell batteries of the same size and 5-10% higher than that of aluminum-shell batteries. They have become the first choice for color-screen mobile phones and MMS phones. Most of the new color-screen and MMS phones on the market now also use polymer batteries.

10. Small internal resistance

The internal resistance of polymer batteries is smaller than that of general liquid batteries. At present, the internal resistance of domestic polymer batteries can even be below 35mΩ, which greatly reduces the self-consumption of batteries and prolongs the standby time of mobile phones, which can fully reach the level in line with international standards. This 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 nickel-hydrogen batteries.

11. The shape can be customized

Manufacturers are not limited to standard shapes and can economically make the right size. Polymer batteries can increase or decrease the thickness of the battery cell according to customer needs, develop new battery cell models, are cheap, have a short mold opening cycle, and some can even be tailored to the shape of the mobile phone to make full use of the battery shell space and increase battery capacity.

12. Good discharge characteristics

Polymer batteries use colloidal electrolytes, which have smoother discharge characteristics and a higher discharge platform than liquid electrolytes.

13. Simple protection board design

Since polymer materials are used, the battery cells will not catch fire or explode, and the battery cells themselves are sufficiently safe. Therefore, the protection circuit design of polymer batteries can consider omitting PTC and fuses, thereby saving battery costs. [5]

Disadvantages of polymer lithium batteries:

1. The battery cost is high and the electrolyte system is difficult to purify.

2. Circuit protection control is required. Overcharging or over-discharging will destroy the reversibility of the chemical substances inside the battery, thus seriously affecting the battery life.