What are the advantages of li-polymer cylindrical cells and steel case batteries?

What are the advantages of li-polymer cylindrical cells and steel case batteries?

09 May 2020

Li-polymer Cylindrical Cell

The soft pack lithium battery is a liquid lithium ion battery with a layer of polymer shell. The biggest difference from other batteries is the flexible packaging material (aluminum-plastic composite film), which is also the most critical and technically difficult material in the soft pack lithium battery . The packaging materials and structure of the soft-pack battery give it many advantages.

Cylindrical Pouch Cell
                                    18400 Cylindrical Pouch Cell

Steel Case Battery

Cylindrical batteries are still the most common type we have seen, mainly steel cylindrical cylindrical lithium iron phosphate batteries. The performance of this battery is high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, high current discharge, stable electrochemical performance, safe use, wide operating temperature range, and environmental friendliness. Widely used in solar lamps, lawn lamps, backup energy, electric tools, toy models.

Advantages of Cylindrical Pouch Cell

Good safety performance: The electrolyte of the soft-pack battery is less leaking, and the soft-pack battery will burst and burst in the case of safety hazards. In those less common cases, the bag cells will only swell. The cylindrical battery is usually wrapped in an iron sleeve. Therefore, when pressure is established in the cylindrical battery, the end of the cylindrical battery is fixed by other batteries or casings, and they may explode, resulting in dangerous safety hazards.

Light Weight

The weight of the soft-pack battery is 40% lighter than that of the steel battery square battery of the same capacity, and 20% lighter than the aluminum battery square battery.

Large Battery Capacity

The soft pack saves 20% of the volume, which is 50% higher than the steel battery of the same size and 20-30% higher than the aluminum battery. Compared with a cylindrical battery, the energy storage capacity of a pouch battery is much greater in a given physical space.

Li-ion cylindrical battery
                                       16400 Cylindrical Pouch Battery

Good Cycle Performance

The cycle life of the soft-pack battery is longer, and the 100-cycle attenuation is 4% to 7% less than that of the aluminum case.

Small Internal Resistance

The internal resistance of the soft-pack battery is smaller than that of the lithium battery. The minimum domestic resistance can be less than 35mΩ, which greatly reduces the self-consumption of the battery.

Flexible Design

Can be customized according to customer needs, can be made thinner, ordinary aluminum shell can only achieve 4mm, soft package can achieve 0.5mm.

The Trend of Li-polymer Cylindrical Cell

There is no doubt that the market trend is to increase the utilization rate of bag cells, which is due to the greater flexibility of the shape of the bag cells and the ability to produce fashionable appearance products. The advantage of low internal resistance is also more attractive, and the longer battery life also reduces the additional cost for customers to replace batteries / products. Our customers can use this as a big selling point to attract new users, which is very suitable for wearable devices, smart phones, speakers and other 3C products.

The advantages of flexible packaging batteries in terms of safety and energy density have also received increasing attention. Judging from the capacity of the new power battery this year, flexible packaging batteries account for 30%. Industry experts predict that with the development of battery routes, the penetration rate of soft pack batteries in the new energy vehicle market will continue to increase. In the future, soft pack batteries will account for more than 50% of all types of batteries.