Lithium-free battery and lithium polymer battery which is better

Lithium polymer batteries are upgraded products of lithium ion batteries. Compared with the current popular lithium-ion battery, it has the advantages of large capacity, small size (thin), and safety (no explosion). However, due to the time required for the replacement of the entire industry chain, its cost (cost) is still relatively high, and it is only used in high-end digital products (ultra-thin notebook computers, etc.).

Predictably, lithium polymer batteries will replace existing lithium-ion batteries in the next 5-10 years! In fact, in the electronics industry more developed countries such as Japan and South Korea lithium polymer batteries have reached a certain level of penetration, but China is still relatively backward in this respect, let's wait and see! I 'll have to replace one of these safer ones when the lithium polymer batteries are cheap in the near future!

Lithium polymer battery (Li-polymer, also known as polymer lithium battery): It has a variety of obvious advantages such as high energy density, smaller size, ultra-thin, light weight, high safety and low cost. battery. In terms of shape, the lithium polymer battery has an ultra-thinning feature and can be fabricated into a battery of any shape and capacity in accordance with the needs of various products. The battery can reach a minimum thickness of 0.5 mm. Compared to lithium-ion batteries, lithium polymer batteries have the following characteristics:

1. No battery leakage problem, the battery does not contain liquid electrolyte inside, and uses colloidal solids.

2. Can be made into a thin battery: with a capacity of 3.6 v400mah, the thickness can be as thin as 0.5 mm.

3. The battery can be designed in a variety of shapes.

4. The battery can be bent and deformed: the polymer battery can be bent up to about 90°.

5. A battery that can be made into a single high voltage: liquid electrolyte can only obtain high voltage in series with several batteries, and the polymer battery can be made into a multi-layer combination in a single piece to achieve a high voltage because it has no liquid itself.

6. The capacity will be twice as high as the same size lithium-ion battery.

First of all, from the structural point of view, the full name of the lithium polymer battery should be a lithium ion polymer battery, so it seems that the lithium polymer battery is actually a kind of lithium ion battery. The biggest difference between the two is that the electrolyte used in the interior is different. The lithium ion battery uses a liquid electrolyte, while the polymer lithium ion battery is replaced by a solid polymer electrolyte. The polymer can be solid or It is semi-solid (gelatinous).

Secondly, from the appearance, most of the mobile power products currently on the market use cylindrical (18650) lithium-ion batteries or bulk lithium polymer batteries, so when we choose mobile power, if The type of battery used in the product packaging does not specify the type of battery used, so you can simply understand the type of battery used internally by the thickness of the product itself.

It can be said that after years of development, the technology of lithium-ion batteries is relatively mature, and the mass production has made its manufacturing cost very low. Therefore, lithium-ion batteries are more advantageous in price than lithium polymer batteries. This is why it is used in most laptops and other devices.

Since lithium ions using a liquid electrolyte will increase their internal pressure in the case of overcharging (overcharging), in order to avoid explosion of the sealed metal casing,usually this 18650 battery has a safety valve at the top. When the internal pressure of the battery is too large, the top relief valve will automatically pop up to reduce the pressure. However, when the safety valve is ejected, the lithium ions leaking inside the battery may still be ignited due to contact with oxygen in the air.

Compared with lithium ion batteries using liquid electrolytes, lithium polymer batteries using solid polymer electrolytes are ultra-thin in shape, with a theoretical minimum thickness of 0.5 mm, and any shape and arbitrary area. . The battery styling flexibility is greatly improved, so that a new generation of lithium batteries of any shape and capacity can be better formed.

Therefore, for electronic products using such lithium-ion batteries, there are very high requirements on their internal charge and discharge protection IC. However, with the development of lithium-ion batteries for many years, both the design of the batteries themselves and the respective The technical level of a kind of protection IC is very mature. As long as we can use it properly in daily use and avoid the phenomenon that the battery is pierced by hard objects, the 18650 battery is still very safe, otherwise most notebooks on the market also Will not use this battery.

In a strict sense, lithium polymer batteries are the same as lithium ion batteries using liquid electrolytes because they are the same in the positive electrode, the negative electrode and the electrolyte. The only difference is the difference between the diaphragm and the packaging material. Therefore, fundamentally speaking, Lithium polymer batteries are also a type of lithium ion batteries.

Summary: In fact, whether it is a steel-shell lithium-ion battery or a soft-packed lithium-ion battery, the performance in safety performance is very good. After all, the production technology of lithium-ion battery is very mature, as long as it avoids high temperature and short circuit in daily use. The occurrence of overcharge, piercing, etc., can avoid the occurrence of unexpected "explosions", fires and other unexpected situations. For the lithium-ion battery and lithium polymer battery that we often say, both have their own advantages and disadvantages. If you prefer the cost-effectiveness of the product, choose 18650 battery, if you prefer the appearance and volume of the mobile power supply. Then, the slightly more expensive lithium polymer battery is the first choice.

Whether it is a steel shell lithium-ion battery mobile power supply or a soft-pack lithium-ion battery mobile power supply, the performance in terms of safety performance is very good. After all, the production technology of lithium-ion battery is very mature, as long as it avoids high temperature during daily use. Short-circuit, over-charge, piercing and other situations can avoid the occurrence of unexpected situations such as "explosions" and fires. For the lithium-ion battery mobile power source and the lithium polymer battery mobile power source that we often say, both have their own advantages and disadvantages. If the price/performance ratio of the mobile power source is biased, the 18650 battery is selected, if it is biased toward the mobile power source. Appearance and volume, then the price of a slightly more expensive lithium polymer battery is the first choice.

According to the different electrolyte materials used in lithium-ion batteries, lithium-ion batteries are divided into liquid lithium-lithium-IonBattery(LIB) and polymer lithium-ion batteries(PolymerLithium-IonBattery, abbreviated as PLB) or plastic lithium-ion batteries(Polylithium-LithiumIonBatteries, abbreviated as PLB). The positive and negative materials used in polymer lithium-ion batteries are the same as liquid lithium-ions. Positive materials are divided into lithium cobalt acid, lithium manganese acid, ternary materials, and lithium iron phosphate materials. Negative graphite, and the principle of battery operation is basically the same. Their main difference lies in the difference in electrolytes. Liquid lithium-ion batteries use liquid electrolytes. Polymer lithium-ion batteries are replaced by solid polymer electrolytes. This polymer can be "dry" or "colloidal". At present, most polymer gel electrolytes are used.

solid

The solid polymer electrolyte lithium ion battery electrolyte is a mixture of a polymer and a salt. The battery has high ionic conductivity at normal temperature and can be used at normal temperature.

gel

The gel polymer electrolyte lithium ion battery adds an additive such as a plasticizer to the solid polymer electrolyte to increase the ionic conductivity and allow the battery to be used at normal temperature.

polymer

Since the solid electrolyte is used instead of the liquid electrolyte, the polymer lithium ion battery has the advantages of being thinner, arbitrarily aread and arbitrarily shaped compared with the liquid lithium ion battery, so that the battery casing can be fabricated from the aluminum-plastic composite film, thereby It can improve the specific capacity of the whole battery; the polymer lithium ion battery can also use the polymer as the positive electrode material, and its mass specific energy will be more than 20% higher than the current liquid lithium ion battery. Polymer Lithium-Ion Battery (PolymerLithium-IonBattery) batteries are characterized by miniaturization, thinness, and light weight. Therefore, polymer batteries will gradually increase in the market.

Polymer lithium ion batteries have the following characteristics:

1 shaping flexibility;

2 higher mass specific energy (3 times the MH-Ni battery);

3 electrochemical stability window width, up to 5 v;

4 perfect safety and reliability;

5 longer cycle life, less capacity loss;

6 volume utilization is high;

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