Take you closer to lithium polymer batteries

In today's era of smartphones becoming thinner and lighter, drones soaring in the sky, and electric vehicles galloping on the road, lithium 

polymer batteries (Li Po) are quietly reshaping our energy experience with their unique advantages. As an upgraded version of lithium-ion 

battery, it replaces traditional liquid electrolyte with gel or solid electrolyte, which not only solves the risk of leakage, but also makes 

breakthroughs in safety, thinness and life, becoming a key support in the field of consumer electronics and green energy.

1、Basic composition: Five layer thin film overlay structure

Lithium polymer batteries are usually composed of five layers of functional thin films stacked through a lamination process, with a total 

thickness as low as 0.1mm and extremely strong plasticity. The functions of each layer are as follows:

First layer: Metal foil collector electrode (negative side)

Copper foil is generally used as the negative electrode current collector, responsible for collecting and conducting electrons. Copper foil 

has good conductivity and ductility, making it suitable for flexible design.

Second layer: Negative electrode material

Most of them are graphite or lithium carbon intercalation compounds (Li-C), which achieve the insertion and extraction of lithium ions 

during the charging and discharging process. Some high-performance batteries use silicon carbon composite materials to enhance their 

capacity.

Third layer: electrolyte membrane

This is the core part of lithium polymer battery, which uses polymer electrolyte, usually polyethylene glycol (PEO) based material or gel 

polymer (GPE). This layer combines ion conduction and electronic insulation functions, completely replacing the liquid electrolyte in 

traditional batteries, fundamentally avoiding leakage and explosion risks. Some systems also add inorganic nano fillers such as SiO₂ 

to enhance mechanical strength and ionic conductivity.

Fourth layer: Positive electrode material

Commonly used are lithium cobalt oxide (LiCoO ₂), lithium manganese oxide (LiMn ₂ O ₄), or lithium iron phosphate (LFP), which are 

responsible for the insertion and release of lithium ions. The positive electrode current collector is usually made of aluminum foil, which 

has both conductivity and support functions.

Fifth layer: Insulation layer and outer packaging

The outermost layer is encapsulated with aluminum-plastic composite film (also known as aluminum-plastic film), which provides physical 

protection and prevents moisture and air from entering. This soft pack design not only reduces weight, but can also be customized into 

trapezoidal, L-shaped, or even bendable shapes according to device requirements.

2、Advantages

(1)Higher security

Lithium polymer battery adopts solid or gel polymer electrolyte, which fundamentally avoids the risk of liquid electrolyte leakage. When 

overcharged, short circuited, or subjected to physical damage such as needle puncture or compression, the battery is less likely to 

explode or catch fire, and only bulging may occur. Experimental data shows that the thermal runaway time in its needle puncture test 

can reach over 120 seconds, much higher than the about 38 seconds of lithium-ion batteries, and its safety performance is more stable. 

In addition, most lithium polymer batteries have built-in protection circuits with overcharge, over-discharge, and short circuit protection 

functions, further enhancing the safety of use.

(2)Flexible design, lightweight and plastic

Due to the use of aluminum-plastic film flexible packaging instead of metal casing, lithium polymer batteries can be made into ultra-thin 

structures with a thickness as low as 0.5mm, suitable for credit card devices or ultra-thin mobile phones. It can also be customized into 

various shapes according to product requirements, such as L-shaped, curved, and even bendable designs (with a maximum bendability 

of about 90 degrees), greatly improving space utilization. This flexibility makes it widely used in space demanding devices such as 

smartphones, smartwatches, TWS earphones, and drones.

(3)High energy density and larger capacity

Under the same volume, the capacity of lithium polymer batteries is usually 5% to 15% higher than that of lithium-ion batteries, and 

some high-quality products can even reach twice as much. Its volumetric energy density can reach 450Wh/dm ³, and its mass energy 

density can exceed 150Wh/kg, which is superior to traditional battery systems. Higher energy density means longer battery life, 

especially suitable for high-power devices such as tablets, aerial drones, and power banks.

(4)Low self discharge rate and long service life

Lithium polymer batteries have a low self discharge rate and can maintain a high level of power even after long-term storage, making 

them suitable for backup power or intermittent use scenarios. Under normal usage conditions, its cycle life can reach over 500 times, 

high-quality products can reach 800 times, and the theoretical service life can reach 3-6 years. Reasonable charge and discharge 

management can further extend its actual service life.

(5)Low internal resistance, excellent discharge performance

Polymer batteries have low internal resistance and can support instantaneous high current discharge. The discharge platform is more 

stable, making them particularly suitable for devices that require high power output such as remote control models and electric tools. 

Meanwhile, its low-temperature performance is superior to traditional lithium-ion batteries, with a capacity retention rate of up to 85% 

at -10 ℃, while the latter is only about 62%.

3、Application

In the era of rapid development of smartphones, drones, and electric vehicles, lithium polymer batteries (Li Po) have become a key 

support for modern energy systems due to their advantages of lightweight, safety, and long lifespan. Compared with traditional 

lithium-ion batteries, it uses gel or solid electrolyte to eliminate the risk of leakage, significantly improving safety and design flexibility.

Its thickness can be as low as 0.5 millimeters, reducing weight by over 30%, and it is widely used in ultra-thin smartphones, wearable 

devices, and drones. Brands such as DJI use this to achieve a battery life of over 30 minutes and high load capacity. In terms of safety, 

the aluminum-plastic packaging and solid electrolyte enable the thermal runaway time in needle puncture testing to exceed 120 seconds, 

which is far superior to traditional batteries and suitable for high safety demand fields such as medical and children's electronics.

Currently, over 90% of high-end consumer electronics products have adopted this technology, and the Apple Watch Ultra achieves a 7-day 

battery life. In industry, inspection drones can cover 50 kilometers of routes in a single operation, increasing efficiency by three times; The 

household energy storage system can cycle up to 1500 times, with a capacity retention rate of over 80%, effectively supporting renewable 

energy sources such as photovoltaic.

Although the energy density is slightly lower and the cost is higher, solid-state battery technology is driving its breakthrough. The future 

energy density is expected to reach 400Wh/kg, with a lifespan of over 2000 cycles, or it may be applied to commercial aerospace and 

deep space exploration. Lithium polymer batteries are driving the arrival of a green and intelligent society with their characteristics of "

light, thin, safe, and long-lasting".