When we choose mobile power, often in the product packaging or brochure to see two different batteries, lithium ion and lithium polymer type, then with them for lithium battery, exactly what are the differences? For some consumers, lithium polymer battery is really better than lithium ion battery?
First of all, from the structure, the full name of lithium polymer batteries should be lithium ion polymer battery, it seems, lithium polymer battery is a lithium ion battery. Is both the biggest difference is that its internal use different electrolyte, lithium ion battery using the liquid electrolyte, polymer lithium ion battery is to instead of solid polymer electrolyte, the polymer can be a solid, or semisolid (gel).
Secondly, from the appearance, currently on the market most of the mobile power supply is sold by using cylindrical lithium ion battery (i.e., 18650) or block two lithium polymer battery. Therefore, when we choose mobile power supply, if the product outer packing is not specified the types of batteries used so you can simply by the thickness of the product itself to its internal battery types used for a general understanding.
Excellent cost performance of lithium ion batteries
Lithium ion battery is a lithium battery of the modified products, due to the lithium chemistry is very lively, so early in the lithium battery when use frequently, burns, and so on and so forth. In order to prevent the lithium metal active chemical property, people in the cathode material of lithium-ion batteries with cobalt, manganese and other metal materials, greatly enhances the safety coefficient of early lithium battery.
Lithium ion battery charging and discharging can be embedded by embedding and take off two process to complete, at the time of discharge, lithium ion removing from the positive electrode materials and electrolyte, again like the water in a sponge into the anode materials, this process is known as embedded. While in charging state, on the other hand, this process is called into the embedded. Above centre-left for lithium battery embedded in the process of the right to take off the embedded process.
After years of development, so to speak, lithium ion battery technology is relatively mature, mass production has made its manufacturing cost is very cheap. So the lithium ion battery is the price advantage more than lithium polymer battery. This is why the majority of devices such as laptop computers will use this batteries.
Due to the use of liquid electrolyte of lithium ion in case of overcharge (excessive charging), will make its internal pressure surge, so to avoid a sealed metal shell exploded, usually this kind of battery will be in the top 18650 is equipped with a safety valve, when the battery internal pressure is too large, the top valve will automatically pop up, in order to have the effect of decompression. But, after the pop-up when the relief valve, internal leaking lithium ion batteries due to the contact with oxygen in the air, still there will be a case of the fire.
So, to use this kind of lithium ion batteries, electronic products, on their internal charge and discharge protection IC has a very high demand. But with many years development of lithium ion battery, as the design in the battery itself and various protection IC technology are very mature, as long as in everyday use, we can do the correct use of the phenomenon of puncture, and avoid the battery was hard objects 18650 batteries are safe, otherwise, the vast majority of laptops on the market will not use the battery.
Higher energy density of lithium polymer batteries
Compared using liquid electrolyte for lithium ion batteries, the use of solid polymer electrolyte lithium polymer battery in shape has the characteristic of ultra-thin, theory of minimum thickness of 0.5 mm, and the characteristics of arbitrary shape and arbitrary area. Has greatly increased the battery modeling flexibility characteristics, thus better able to make any shape and capacity of a new generation of lithium batteries.
In addition, the use of solid polymer electrolyte for lithium-ion batteries, lithium polymer battery compared to common, has a higher energy density, that is to say, under the premise of the same volume, lithium polymer battery has advantages of lighter weight and higher capacity.
If in strict sense, lithium polymer battery in the anode, cathode and electrolyte, and the working principle and the use of liquid electrolyte of lithium ion batteries have the same, the only difference is the diaphragm and the different packing material, therefore, fundamentally speaking, lithium polymer battery is a lithium ion battery.
So, for all kinds of different packaging format lithium-ion batteries, has the following characteristics:
Taken the steel shell of lithium ion battery:
Common to use the steel shell of 18650 batteries, has high safety coefficient, production technology has very mature, and compared with polymer battery is cheaper, occupies most of the lithium battery market share, is most common in the laptop battery.
Taken the soft package of lithium ion battery, polymer battery:
Has higher energy density, better safety performance and characteristics of arbitrary shape, become the most mainstream of choice for digital products batteries, but relative to steel shell of lithium ion battery, the price is still high.
Summary: in fact whether the steel shell or soft package lithium-ion batteries, lithium-ion batteries on the safety performance is very good, after all, the lithium-ion battery production technology is already very mature, as long as in daily use to avoid high temperature, short circuit and overcharge, piercing, and so on and so forth, will be able to avoid what we call the “bang”, fire accidents. We often call for lithium ion batteries and lithium polymer battery, they both have their respective advantages and disadvantages, if you more prefer to the product price, just choose 18650 batteries, if more preference for the appearance of the mobile power and volume, so the price is a bit expensive lithium polymer batteries are preferred.