1, 18650 battery
Generally cylindrical in appearance, suitable for high-current equipment, so almost all notebooks, electric cars [such as Tesla] are designed with 18650 batteries; only super notebook, because of energy saving, Therefore, using li-polymer battery instead of 18650 battery, especially tablets; as for digital cameras, when working, it requires a large voltage and a large current because the charging and discharging of the flash lamp. So the only option is to use battery similar to 18650 battery, whose volume is slightly smaller.
2. Li-polymer battery
Generally cuboid in appearance, small in size and large in capacity. The disadvantage is that the life cycle is shorter than 18650. Due to different designs and materials are used, some of them have liquid inside, while some are dry or colloidal. And the high-current discharge performance is not as good as the 18650 battery. So large-capacity and small-volume electrical equipment usually use li-polymer battery, the typical cases are mobile phones, tablets and other equipment.
1） lower price
The international price of 18650 is about 1USD/pcs, which is about 3RMB/Ah according to 2Ah. While the price of Li-polymer battery is much higher, the low-end factory is 4RMB/Ah, the middle end is 5~7RMB/Ah, and the high end is above 7RMB/Ah. Like ATL, Lishen, who usually sells around 10RMB/Ah, and you are not willing to be accepted if your order is small qty.
2）Can’t be customize
SONY has always wanted to make li-polymer battery the same as alkaline batteries. There are certain industry standards, like the 5th and 7th batteries, which are basically the same in the world. However, one of the great advantages of li-polymer battery is that they can be designed according to the needs of customers. It is impossible to have a unified standard. So till now, the li-polymer battery industry is basically only a standard model of 18650. Others are based on different customers’ requirements.
It’s known that in extreme cases (such as overcharge, high temperature, etc.), li-polymer battery will undergo intense chemical reactions inside and generate a large amount of gas. The 18650 battery uses a rugged metal case. When the internal air pressure reaches a certain level, the steel shell will rupture and explode, causing a terrible accident. This is why rooms that test 18650 batteries generally must be protected by layers, and no admittance when testing. Li-polymer battery do not have this problem. Even in extreme cases, because of the low strength of the packaging, as long as the air pressure is slightly higher, it will rupture and will not cause explosion. The worst consequence is burning. Therefore, the Li-polymer battery is superior to the 18650 battery in terms of safety.
4） Low energy density
The average 18650 battery capacity is about 2200mAh, so the energy density is about 500Wh/L, while the energy density of the li-polymer battery can be close to 600Wh/L. But i-polymer battery also has its own drawbacks. Mainly because of the higher cost, because it can be designed according to customer needs, the research and development costs inside should be counted. Moreover, the variety of shapes and types, resulting in various fixtures in the manufacturing process are non-standard parts, which increased cost correspondingly.