Briefly describe the development trend of polymer lithium ion batteries

First, the characteristics of polymer lithium-ion battery

Lithium -ion batteries can be classified into liquid lithium ion batteries (LIB) and polymer lithium ion batteries (LIP) according to the electrolyte materials used in lithium-ion batteries. The positive and negative materials used in the polymer lithium ion battery are the same as the liquid lithium ions, and the working principle of the battery is basically the same. The main difference is that the electrolyte 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 either "dry" or "glue". Most of them currently use polymer colloidal electrolytes. Polymer lithium-ion batteries can be divided into three categories:

(1) Solid polymer electrolyte lithium ion battery. The electrolyte is a mixture of a polymer and a salt. The battery has low ionic conductivity at normal temperature and is suitable for high temperature use.

(2) Gel polymer electrolyte lithium ion battery. That is, an additive such as a plasticizer is added to the solid polymer electrolyte to increase the ionic conductivity, so that the battery can be used at normal temperature.

(3) A lithium ion battery of a polymer positive electrode material. Conductive polymer is used as the positive electrode material, and its specific energy is three times that of the existing lithium ion battery. It is the latest generation of lithium ion battery. Since the liquid electrolyte is replaced by a solid electrolyte, the polymer lithium ion battery has the advantages of being thinner, arbitrarily aread, and arbitrarily shaped, and does not cause leakage, combustion, explosion, and the like. The problem is that the battery casing can be made of aluminum-plastic composite film, so that the specific capacity of the whole battery can be improved; the polymer lithium ion battery can also use the polymer as the positive electrode material, and the mass ratio energy will be higher than the current liquid lithium ion battery. Increase by more than 50%. In addition, polymer lithium-ion batteries are more efficient than lithium-ion batteries in terms of operating voltage, charge and discharge cycle life, and the like. Based on the above advantages, the polymer lithium ion battery is known as the next generation lithium ion battery.

Second, the comparison of polymer batteries and liquid lithium batteries

Due to the different production processes of various manufacturers, the polymer lithium battery currently on the market is divided into two types: winding type (represented by Sony and Toshiba) and laminated type (represented by TCL and ATL), but the specifications adapted to the demand of mobile phones. Most are below 4mm thickness. Compared with the liquid state, the thinner the polymer film is, the thinner the steel and aluminum shell is, and the production method is different from the liquid lithium battery. The thinner the polymer, the better is the production. Theoretically, the battery with a thickness of less than 0.5mm can be produced. Liquid lithium battery is just the opposite. The thicker the better the production, the battery with a thickness of less than 4mm is difficult to produce. Even if it is produced, the capacity is obviously not as good as that of polymer lithium battery, and the cost is not superior. Thus, the thinner the battery, the lower the polymer production cost and the higher the liquid production cost. However, on thicker specifications (such as the current mainstream model of mobile phone lithium battery 053048\053448\063048\063450 and similar specifications), the liquid lithium battery supply chain is mature, the process is mature, the production efficiency is high, and the yield is high. Strong manufacturing cost advantage. From the current market point of view, the liquid lithium battery of the 5mm, 6mm thickness series is much higher than the 3mm, 4mm thickness series battery, but the price is much lower. In theory, the material cost of the 5mm and 6mm thickness specifications is close to that of the liquid. However, the current process cost of the 5mm and 6mm series batteries is much higher than that of the liquid. Therefore, it is necessary to compete with the liquid in this specification. There are still many distances.

Third, the development trend of polymer lithium ion

Polymer lithium-ion batteries have been matured and commercialized in the world for more than two years. Although the sales volume is growing rapidly, its market share is still less than 10%, which is incomparable with the market share of liquid lithium batteries of 90%, which is much lower than People's expectations. For various reasons, the price of polymers on the market is generally higher than that of liquid lithium batteries. However, because the competition mode of mobile appliances is quietly changing, especially the design value of polymer batteries for mobile appliances (such as 4mm) Polymer batteries are being recognized by more and more designers such as mobile phones and mobile DVDs. The polymer manufacturers are still confident that the polymer era will come. The development trend of polymer lithium ion batteries can be seen from the development of mobile phones. At present, mobile phones have the following development trends:

(1) The mobile phone itself is developing in the direction of miniaturization and ultra-thinness to facilitate the carrying of consumers;

(2) The personalization of mobile phone design, the performance concept is no longer the original square shape, the irregular shape and curved surface design shape has become the mainstream of mobile phone design aesthetics;

(3) The use of color screens and mobile phone functions continues to increase. In order to miniaturize the mobile phone, battery reduction and thinning are the most effective ways. The thickness of the battery below 4mm has become the mainstream trend of thin mobile phone configuration. In terms of cost performance, this is the specialty of the polymer. The effective space left by the mobile phone with irregular shape, curve and curved surface design becomes an irregular shape. The liquid rectangular shape does not make efficient use of space and has a low capacity, and the laminated polymer can make the most efficient use of such irregular space to enlarge the capacity. Recently, the arc-shaped battery, trapezoidal battery, and backpack battery introduced by TCL Jinneng Company can increase the capacity of the mobile phone by more than 50% compared with the liquid battery with the corresponding specifications. More and more mobile phones are functioning, resulting in more and more power consumption. The battery capacity is required to increase accordingly. Polymer batteries have significant advantages without increasing the thickness of the battery. Similarly, notebook computers, Bluetooth headsets, PHS phones, mobile DVDs and other appliances are moving in the direction of mobile and portable, all equipped with liquid crystal display, and the functions are increasing, and the LCD screen is constantly increasing. These provide unlimited business opportunities for polymer lithium-ion batteries.

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