Lithium battery and polymer lithium battery

Li-polymer battery (li-polymer battery) : compared with previous batteries, there is much more energy, miniaturization and light weight, which is a kind of chemical battery.

In the shape of lithium polymer battery, lithium polymer battery has the characteristics of ultra-thin, can cooperate with the needs of some products, made into different shapes and capacity of the battery. The minimum theoretical thickness of this type of battery can be up to 0.5mm.

The three elements of a typical battery are the anode, the cathode, and the electrolyte. The so-called lithium polymer battery refers to at least one or more of the three elements of the battery system using polymer materials. In the lithium polymer battery system, the polymer materials are mostly used in the anode and electrolyte. The anode materials are conductive polymers or inorganic compounds commonly used in lithium ion batteries, while the cathode materials are lithium metals or lithium carbon interlayer compounds. The electrolytes are solid or colloidal polymer electrolytes or organic electrolytes. Since lithium polymer has no excess electrolyte, it is more reliable and stable.

According to the electrolyte materials that are used in lithium ion batteries, lithium ion batteries are divided into liquid lithium ion battery (Liquified Lithium - Ion Battery, LIB for short) and polymer lithium ion battery (Polymer Lithium - Ion Battery, for PLB) or plastic lithium ion battery (Plastic lithium ion batteries, for PLB). The positive and negative electrode materials used in polymer lithium ion batteries are the same as liquid lithium ions. The positive electrode materials are divided into lithium cobalt acid, lithium manganese acid, ternary materials and lithium iron phosphate materials, and the negative electrode graphite. The working principle of batteries is basically the same. The main difference between them is the difference in electrolyte. Liquid lithium ion batteries use liquid electrolyte, while polymer lithium ion batteries use solid polymer electrolyte instead. This kind of polymer can be "dry" or "colloidal".

Battery is mainly based on lithium as the other pole, which generally USES liquid electrolyte. Nowadays, it is mainly based on LiPF6 and LiClO4 dissolved in DMC:EC(v:v=1:1) electrolyte. Some of them have been modified, but they are still liquid batteries. Polymer lithium-ion batteries, from the Angle of the internal battery materials, mainly is the internal is a polymer electrolyte, here is generally gel electrolyte and solid electrolyte, if memory serves, south Koreans have been published to the PEO - ionic liquid electrolyte of gel battery, don't know if Galaxy Round or LGGFlex have used such a battery. Of course, there are also lithium batteries with all-solid electrolytes such as LiPON, NASICON, perovskite and LiSICON, which are ceramic electrolytes with high conductivity or glass electrolytes composed of amorphous substances. If they are to be classified, they should be classified as lithium secondary batteries, but this is an expansion of the concept. Secondly, lithium polymer battery box lithium battery slightly different in the packaging, lithium battery is generally in steel (18650 or button type 2320), and lithium polymer battery to aluminum plastic packaging film as the packaging, that is, soft pack battery.

The concept of lithium battery includes lithium ion battery and lithium polymer battery. Lithium ion battery is divided into liquid electrolyte lithium ion battery and polymer electrolyte lithium ion battery according to the state of room temperature of electrolyte. Polymer batteries, which have solid or gel electrolytes, are "advanced" over liquid electrolytes used in ordinary lithium-ion batteries. In the production, liquid electrolyte, after the completion of the core into the shell, to injection, injection liquid electrolyte; Polymer batteries, on the other hand, are coated with positive and negative carriers or coated with film before packaging with aluminum, before lamination of positive and negative electrodes, and injected with liquid electrolyte at a temperature slightly lower than room temperature. After that, the electrolyte becomes gel state (polymer state).

solid

Solid polymer electrolyte lithium ion battery electrolyte is a mixture of polymer and salt. This kind of battery has high ionic conductivity at room temperature and can be used at room temperature.

gel

Gel polymer electrolyte lithium ion battery is solid polymer electrolyte in addition to plasticizer and other additives, so as to improve the ionic conductivity, so that the battery can be used at room temperature.

polymer

As solid electrolyte replaces liquid electrolyte, compared with liquid lithium ion battery, polymer lithium ion battery has the advantages of thinness, arbitrary area and arbitrary shape. Therefore, the battery shell can be made of aluminum plastic composite film, which can improve the specific capacity of the whole battery. Polymer lithium ion battery can also be used as a positive polymer material, the mass specific energy will be more than 20% higher than the current liquid lithium ion battery. Polymer lithium ion (Polymer Lithium - Ion Battery) battery has the characteristics of miniaturization, thin, lightweight. Therefore, polymer batteries in the market share will gradually increase.

Lithium polymer battery is made of filing alloy as the positive electrode, using conductive polymer materials, polyacetylene, polyaniline or polyp-phenol as the negative electrode, organic solvent as the electrolyte. The specific energy of lithium polyaniline battery can reach 350W. H /kg, but the specific power is only 50-60w /kg, the service temperature is -40-70 degrees, the service life is about 330 times.

Compared with lithium ion batteries, lithium polymer batteries have the following characteristics:

1. Relatively, the problem of battery leakage is improved, but not completely.

2. Can be made into thin battery: with a capacity of 3.6V250mAh, its thickness can be as thin as 0.5mm.

3. The battery can be designed in various shapes.

4. Single high voltage can be made: liquid electrolyte battery can only be a few batteries in series to get high voltage, and polymer battery because of its own no liquid, can be made in a single multi-layer combination to achieve high voltage.

5. Discharge power, theoretically 10% higher than a lithium-ion battery of the same size.

Li-polymer battery (li-ion polymer battery) has many advantages, such as high specific energy, miniaturization, ultrathin, light weight and high security. Based on such advantages, lithium polymer batteries can be made into any shape and capacity of the battery, so as to meet the needs of various products; And it USES aluminum packaging, internal problems can be immediately through the outer packaging, even if there are safety hazards, will not explode, only bulge. In polymer batteries, the electrolyte plays a dual role as a separator and an electrolyte: on the one hand, it separates the positive and negative electrode materials like a separator to prevent self-discharge and short circuit inside the battery; on the other hand, it conducts lithium ions between the positive and negative electrodes like an electrolyte. Polymer electrolyte not only has good electrical conductivity, but also has the unique characteristics of polymer materials, such as light weight, good elasticity, easy to film, which also conforms to the development trend of light weight, safety, high efficiency and environmental protection of chemical power supply

Polymer lithium ion batteries have the following characteristics [1] :

(1) shape flexibility;

(2) higher mass specific energy (3 times than mh-ni battery);

(3) electrochemical stable window width, up to 5V;

(4) perfect safety and reliability;

(5) longer cycle life, less loss of capacity;

(6) High volume utilization;

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