Explain the difference between lithium ion battery and lithium polymer battery

When we choose mobile power, it is often in the product packaging or brochure. There are lithium ion and lithium polymer two different types of batteries. What are the differences? For some consumers, is lithium polymer battery better than lithium ion battery? This article will introduce these two batteries on price, performance and security.

First of all, from the structure, lithium polymer battery should be the full name of lithium-ion polymer battery, it seems, lithium polymer battery is also a kind of lithium ion batteries. Is the biggest difference is that both the electrolyte is different, the internal use of lithium ion battery is a liquid electrolyte, and polymer lithium ion batteries with solid polymer electrolyte as a substitute for, the polymer can be solid, can also be a semi-solid (gel).

Cylindrical lithium-ion battery

Secondly, from the appearance, at present the majority of mobile power supply that is sold on the market is the use of cylindrical (18650) of the lithium ion battery or block two lithium polymer batteries. Therefore, when we choose mobile power, if the product outer packing not specified the type of batteries, so you can simply by the thickness of the product itself to its internal the type of battery for a general understanding.

Is the improved product of lithium-ion batteries, lithium ion batteries due to the lithium chemistry is very lively, so early lithium battery when use frequently, burning, and so on and so forth. In order to prevent the lithium metal active chemical properties, people through the anode material in lithium-ion batteries with cobalt, manganese and other metal materials, greatly enhances the safety coefficient of early lithium batteries.

Lithium ion battery embedded and embedded

Lithium ion battery charging and discharging can be embedded by embedding and take off two processes to complete, at the time of discharge, lithium ion removing from the positive electrode materials and electrolyte, again like water in a sponge into the anode materials, a process called embedded. While in charging state, on the other hand, this process is called into the embedded. Left lithium battery into the embedded process, and left the right to take off the embedded process.

The most common 18650 battery

Can say after years of development, the lithium ion battery technology is relatively mature, mass production has made the manufacturing cost is very low. So the lithium ion battery is the price advantage more than lithium polymer batteries. That is why most of today's devices such as laptop computers will use this battery.

18650 battery structure

Due to the use of liquid electrolyte of lithium ion in the case of overcharge (overcharge), will make its internal pressure surge, so in order to avoid the 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 safety valve will automatically pop up, to have the effect of decompression. But when the relief after the pop-up, internal leaking lithium ion batteries due to contact with oxygen in the air, still can appear the situation of the fire.

So, to use this kind of lithium ion batteries, electronic products, on its internal charge and discharge protection IC has very high requirements. But with many years development of lithium ion battery, whether the design of the battery itself or other protection IC technology are very mature, as long as in the daily use, we can do it the right to use and avoid the phenomenon of cell was hard pierced, 18650 batteries are very safe, otherwise on the market most of the laptop will not use the battery.

Compared to the use of liquid electrolyte for lithium ion batteries, the use of solid polymer electrolyte of 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. Greatly improved the characteristics of the battery model flexibility, thus can make any better shape and the capacity of a new generation of lithium batteries.

Lithium polymer battery

In addition, the use of solid polymer electrolyte for lithium ion battery lithium polymer battery compared to common, has a higher energy density, that is to say, on the premise of the same volume, lithium polymer batteries with lighter weight and higher capacity, etc.

Lithium polymer battery more frivolous

If in a strict sense, lithium polymer battery in the anode, cathode and electrolyte and working principle and the use of liquid electrolyte of lithium ion battery is the same, the only difference is the diaphragm and the different packing material, therefore, fundamentally, lithium polymer battery is also a kind of lithium ion batteries.

So, for all kinds of different packaging format lithium-ion batteries have the following characteristics:

Taken the steel shell of lithium ion battery:

Common steel 18650 battery shell, for use with high safety factor, production technology has been very mature, and compared with polymer battery is cheaper, most of the lithium battery market share, the most common in the laptop batteries.

Taken the soft package of lithium ion battery, polymer battery:

With higher energy density, better performance and safety performance characteristics of arbitrary shape, become the most mainstream of choice for digital products batteries, lithium ion battery, but relative to steel shell price still on the high side.

Summary: in fact, steel shell and soft package lithium-ion batteries have good safety performance. After all, the current 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, it is able to avoid what we call "explosion", the occurrence of accidents such as fire. We often call for the lithium ion battery and lithium polymer battery. Both of them have their respective advantages and disadvantages. If you more care about product price, you can choose 18650 battery. If you more care about the appearance of the mobile power and volume, you should buy expensive lithium polymer battery.

The page contains the contents of the machine translation.