Lithium battery classification and advantages and disadvantages of polymer lithium batteries

Although we use lithium batteries every day, do you really understand them? Lithium batteries are mainly divided into several categories, which are used on mobile phones and Charge Pal... Let's talk briefly.

Lithium battery classification

There are two main types of lithium batteries that are widely used nowadays: one is a polymer lithium battery.

Smart phones such as the iPhone use polymer batteries ; the second is lithium-ion batteries , which represent 18650 batteries. This type of battery is similar to the common No. 5 battery, and is used in charging treasures and high-end balance cars.

Lithium-ion batteries use liquid electrolytes, while polymers

lithium ion battery

It is replaced by a solid polymer electrolyte, which may be solid or semi-solid (gelatinous).

How to differentiate?

The hard aluminum shell or steel shell is packaged with a liquid lithium battery, and the aluminum plastic film is a polymer lithium battery. The silver-colored aluminum plastic film is light and thin, like a paper sheet, and has a good folding and bending effect. The hard shell is generally a steel shell or an aluminum shell, and the outer shell shape is fixed and cannot be folded or bent.

Which is better?

In theory, the polymer lithium battery is the highest technology lithium battery, which is better than the 18650 battery, but it is not absolute. The 18650 battery also has the advantage that people can't refuse.

Advantages and disadvantages of polymer lithium batteries

Advantage

(1) Good safety performance.

Lithium polymer battery

The structure is made of aluminum-plastic flexible packaging, which is different from the metal casing of the liquid battery. Once a safety hazard occurs, the lithium-ion battery core is easy to explode, and the polymer battery core is only gas-burning, and at most it burns.

(2) Smaller thickness can be made thinner

Ultra-thin, the thickness can be less than 1mm, and can be assembled into a credit card. There is a technical bottleneck in the thickness of ordinary liquid lithium batteries below 3.6mm, and the 18650 battery has a standard size.

(3) Light weight and large capacity

Using polymer

The electrolyte battery does not require a metal shell as a protective outer package, so when the capacity is the same, it is 40% lighter than the steel case lithium battery and 20% lighter than the aluminum case battery. When the volume is generally large, the capacity of the polymer battery is larger, about 30% higher.

(4) Shape can be customized

Polymer batteries can increase or decrease the thickness of the battery according to actual needs, such as Apple's new MacBook

It is a trapezoidal polymer battery that makes full use of the internal space.

2. Faults

(1) The cost of the battery is high, 1-5 times more expensive than the 18650 lithium battery, look at the manufacturer. The 18650 battery is cheap, which is why most of the charging treasures like Yubo and Pinsheng use 18650 batteries.

(2) As long as it is broken, it will be completely abolished, and it is necessary to protect the line control. Overcharge or over discharge will destroy the reversibility of the internal chemical substances in the battery, thus seriously affecting the life of the battery.

Polymer battery

The shortcoming is the advantage of the 18650 battery, and can form a battery array. For example, Tesla Models uses 8000 18650 batteries (produced by Panasonic). Even if a single battery explodes, only 1/8000 will explode. Replace this.

What's more, the 18650 battery of the big manufacturers now has a safety valve on the top. When the internal pressure of the battery is too large, the top safety valve will automatically pop out to relieve the pressure, which is difficult to explode.

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