According to the classification of electrolytic materials, lithium ion batteries can be divided into liquid lithium ion batteries and polymer lithium ion batteries. Due to the relatively high cost of lithium polymer batteries, their market share is relatively low. Liquid lithium batteries are widely used in the field of electric vehicles. In terms of electric vehicle applications, lithium polymer batteries are being commercialized. With technological advancements and the realization of large-scale production, the cost of lithium polymer batteries is expected to decrease rapidly and the penetration rate is expected to further increase.
Main listed companies in lithium battery industry: CATL (300750.SZ), Guoxuan Hi-Tech (002074.SZ), Yiwei Lithium Energy (300014.SZ) , Desai Battery (000049.SZ), Narada power supply (300068.SZ), etc.
Main dataes of this article:Battery thickness, weight, capacity, internal resistance, cycle time, permeability, etc.
Lithium-ion batteries can be divided into lithium batteries -liquid ion and polymer lithium-ion batteries
The electrolyte used in lithium-ion batteries is generally composed of organic solvents and lithium salts dissolved in them. the solvents currently used are mainly carbonate compounds (divided into two categories: PC-based and EC-based).
Lithium-ion batteries can be divided into liquid lithium-ion batteries and polymer lithium-ion batteries. Lithium-ion polymer batteries are developed from liquid lithium-ion batteries in addition to organic solvents and lithium salts. Polymer electrolytes also contain a pure solid/gel type polymer.
The difference between the two types of battery materials mainly liesmainly in the electrolyte
Since the positive and negative electrode materials used in liquid lithium-ion batteries and polymer lithium-ion batteries are the same, the difference mainly lies In the electrolyte, the electrolyte of liquid lithium ion battery is liquid and the electrolyte of polymer lithium ion battery is semi-solid colloid or pure solid.
The difference in the materials of the electrolyte affects the material of the two shells, the choice of separators and current collectors. Compared with liquid lithium batteries, the outer packaging of lithium polymer batteries uses thinner aluminum film, which is thinner than steel and aluminum shells. However, when the thickness of the battery is the same, the material cost of lithium polymer batteries is the same. that of liquid lithium batteries. Close, but the cost of the process is much higher than the latter ;
In lithium polymer batteries, the electrolyte plays the dual function of separator and electrolyte: 1) Separates the positive and negative electrode. materials like a separator, making the battery no self-discharge or short circuit occurs internally; 2) The electrolyte acts as a conductor to conduct lithium ions between the positive and negative electrodes.
The occupancy rate of lithium polymer batteries is relatively low
The thickness of lithium polymer batteries can theoretically reach 0.5mm, which conforms to the requirement of mobile phones whose battery thickness is 4mm and the following requirements: Compared with liquid lithium batteries, lithium polymer batteries are lighter for the same capacity and have a higher capacity for the same size; 35 mΩ. Significantly reduces battery self-consumption.
Compared to Li batteriesLiquid thium, lithium polymer batteries have higher energy density, are more customizable, lighter and safer. However, due to their higher cost than liquid lithium batteries, the market share of lithium polymer batteries is relatively small.
The application areas of these two types of batteries continue to expand
Liquid lithium-ion batteries are widely used in electronic products 3C, electric vehicles, industries Markets and other fields, relying on their cost-effective advantages, have been applied to notebook computers, camcorders, large-scale energy storage and other markets. As the performance of liquid lithium-ion batteries improves, their application areas are also constantly expanding, such as power tools, electric toys, telephones and electronic devices.swim.
Lithium polymer batteries have fine characteristics and can meet product needs. Lithium-ion polymer batteries are mainly used in mobile phones, Bluetooth headsets, laptops, etc. As its technology continues to mature and prices continue to decline, the potential application areas of lithium-ion polymer batteries include electric vehicles, small radios and walkie-talkies, electric bicycles, military fields, etc. .
According to data from Gaogong Lithium Battery, the penetration rate of lithium polymer batteries in the field of electric vehicles is low. In 2020, liquid lithium batteries (cylindrical and square batteries) accounted for 90.5% of shipments in the energy sector. vehicle field %. In terms of applications for electric vehicles, lithium polymer batteries are in progressmarketing.
The penetration rate of lithium-ion polymer batteries is expected to further increase
At present, most lithium-ion polymer batteries are found in laboratory. pilot phase, and their costs are relatively high. It is still not comparable to liquid batteries, but with technological advances and the realization of large-scale production, its cost is expected to decrease rapidly. Polymer solid electrolytes based on PEO or PEO-like membranes are expected to accelerate the commercialization process, thereby increasing the penetration rate of lithium-ion polymer batteries.
—— For more detailed research and analysis of this industry, please see the"Analysis Report of Demand Forecasting and Strategic Investment Planning of China Industry lithium batteries" from the Qianzhan Industry Research Institute"
Lithium polymer batteriesare very good. The advantages of this battery are:
1. High tension. The working voltage of a single battery can reach 3.6V~3.8V, which is much higher than the 1.2V voltage of nickel-metal hydride and nickel-cadmium batteries.
2. High capacity density. Its capacity density is 1.5 to 2.5 times that of nickel-metal hydride batteries or nickel-cadmium batteries.
3. Small self-discharge. It also loses very little capacity after being left for a long time.
4. Long life expectancy. Its lifespan can reach more than 500 times under normal use conditions.
5. There is no memory effect, there is no need to drain the remaining power before charging, and it is easy to use.
6. Good safety performance. Lithium polymer batteryThe battery structure usesa flexible aluminum-plastic packaging, which is different from the metal casing of the liquid battery. Once a safety hazard occurs, the liquid battery explodes easily, while the polymer battery only swells.
7. Small thickness. It can be made thinner, ultra-thin, and the battery can be assembled into a credit card.
8. Big capacity. Polymer batteries have 10-15% more capacity than steel-shelled batteries of the same size and 5-10% more capacity than aluminum-shelled batteries.