Lithium-ion batteries are secondary (rechargeable) batteries that rely on lithium ions moving between positive and negative electrodes. There are three key types of lithium-ion battery packaging: cylindrical, square and soft package. Different packaging structures represent different characteristics, and they all have advantages and disadvantages.
1. Cylindrical lithium-ion batteries
Cylindrical lithium batteries are divided into lithium iron phosphate batteries, lithium cobalt oxide batteries, lithium phosphate batteries, cobalt manganese batteries and three-dimensional materials. At present, the main performance of Li-Fe-P battery is large volume, high output voltage, good battery charging cycle, stable output voltage, large charge and discharge current, stable photocatalytic performance, high operating temperature, environmental protection. Widely used in solar lamps, lawn lamps, power storage, pneumatic tools, toy models, etc.
A typical cylindrical rechargeable battery consists of a cover, valve, PTC assembly, open current, seal ring, positive phase, negative phase, protective film and housing.
In 1991, SONY of Japan invented the first cylindrical lithium-ion battery. Because 18650 cylindrical lithium battery has a long history, the market coverage is very high. Cylindrical lithium batteries have many specifications, such as 14650, 17490, 18650, 21700, 26650, etc. Cylindrical lithium-ion batteries are popular in And around Japan.
2. Square lithium-ion batteries
Square lithium battery generally refers to aluminum shell or steel shell square battery, domestic square lithium battery coverage is very high. In recent years, with the popularity of automotive power lithium battery, the difference between mileage and battery power is more and more obvious. Most Chinese power lithium battery manufacturers choose to charge high energy aluminum shell square battery, because the structure of the square battery is simple, different from the shell and other parts of the high explosion-proof valve pressure strength stainless steel plate, so the overall component is light, high performance. Square rechargeable batteries are made by two different processing processes, namely backwire machine and winding.
However, because square lithium batteries can be customized according to the specifications of commodity production, there are many types of specifications in the sales market, but due to the large specifications, it is difficult to unify the processing technology. The application of square batteries in general electronic equipment is not a problem, but for all kinds of serial and serial mechanical equipment products, it is best to use standardized production of cylindrical lithium batteries, so as to ensure the smooth operation of the production process, and it is easier to find rechargeable batteries.
3. Soft pack lithium ion battery
Hard pack lithium battery is a kind of polymer sleeve on liquid lithium battery. The difference between hard pack lithium battery and other rechargeable batteries depends on the plastic soft pack material (plastic composite pack). Plastic flexible packaging materials are generally divided into three layers, namely the outer resistance layer (usually made of polyester or polyester surface protection layer thickness), permeable layer (inner platinum) and inner layer (intelligent high resistance layer).
The packaging and construction of soft-pack batteries give them the following advantages:
(1) Good safety factor: the structure type of flexible packaging battery is aluminum plastic film. In the case of safety risk, the maximum number of flexible packaging battery will be destroyed, rather than an explosion accident like lithium ions in the aluminum shell.
(2). Lightweight: The net weight of the soft coating battery is 40% lighter than that of the same size aluminum shell lithium battery and 20% lighter than that of the aluminum shell rechargeable battery.
(3). Large capacity: Compared with the aluminum shell battery of the same type, the soft package battery is 1015% and 510% higher than the aluminum shell battery.
(4) Small internal resistance: the internal resistance of the soft sealed battery is small, and the internal resistance of the soft sealed battery core can be guaranteed at least 35m.
(5) Intelligent design scheme: the appearance of soft sealed battery can be customized according to customer requirements, and lithium ion model specifications can be developed.
Soft pack lithium battery current soft pack battery cell model specifications are small, can not meet the market demand;
4. Comparative analysis of three packaging forms of lithium ion battery
Rechargeable battery appearance: Square lithium battery can be any size, so the battery inside the battery.
Multiple performance: Cylindrical lithium ion battery welding multipole lug processing technology is limited, so the multipole lug is slightly weaker than the square collector lug mode
Charge-discharge service platform: the same positive battery material, positive battery material and lithium battery electrolyte are theoretically consistent, but the square battery has slight upward resistance, so the charge-discharge service platform is slightly higher.
Product quality: cylindrical lithium battery processing technology is perfect, the second part of the defect probability is low, quality indicators and automation technology level must be higher than rotary press.
Auricle welding: cylindrical lithium battery electrode lug is easier to weld than square lithium battery, square lithium battery is easier to weld.
Combination: Ring-rechargeable batteries are more relevant and practical, so the combination is simple and works well. Square batteries deal with heat removal.
Structural features: The square battery has weak organic chemical ratio performance, the performance of the battery is significantly reduced after long-term use.
Generally speaking, the advantages and disadvantages of the three types of rechargeable batteries are cylindrical, square and hard pack. Each battery has its own core industry. For example, there are more square lithium phosphate batteries and more than three elements in flexible packaging. With the introduction of new automatic patches, the system software ratio for rechargeable batteries could become a key standard.
