Advantages and disadvantages of rechargeable polymer lithium-ion batteries

Advantages of polymer lithium battery

1. Good safety performance. The rechargeable polymer lithium battery uses aluminum-plastic soft packaging in its structure, which is different from the metal shell of the liquid battery. Once a safety hazard occurs, the lithium ion battery is simply blasted, while the polymer battery will only blow up, and at most it will be incinerated.

2. Small thickness can be made thinner, ultra-thin, thickness can be less than 1mm, can be assembled into credit cards. There is a technical bottleneck for the thickness of ordinary liquid rechargeable lithium batteries below 3.6mm, and the 18650 battery has a standardized volume.

3. Light weight and large capacity. The polymer electrolyte battery does not need a metal shell as a protective outer packaging, so when the capacity is the same, it is 40% lighter than a steel shell lithium battery and 20% lighter than an aluminum shell battery. When the volume is generally large, the capacity of the polymer battery is larger, about 30% higher.

4. The shape can be custom polymer battery can add or reduce the thickness of the battery cell according to practical needs. For example, a new notebook of a famous brand uses a trapezoidal polymer battery to make full use of the internal space.

Defects of rechargeable polymer lithium battery

(1) The main reason is that the cost is higher, because it can be planned according to the customer's needs, and the R&D cost here has to be included. In addition, the variety of shapes and varieties have led to the correct and wrong standard parts of various tooling and fixtures during the production process, and correspondingly increased costs.

(2) The polymer battery itself has poor versatility, which is also brought about by sensitive planning. It is often necessary to plan one for customers from scratch for the difference of 1mm.

(3) If it is broken, it will be completely discarded, and protection circuit control is required. Overcharge or overdischarge will damage the reversibility of the battery's internal chemical substances, which will seriously affect the battery's life.

(4) The lifespan is shorter than 18650 because of the use of different plans and materials, some have liquid inside, some are dry or colloidal, and the performance is not as good as 18650 cylindrical batteries when discharged at high current.