Complete list of cylindrical models for lithium batteries


Battery cell model nominal voltage (V) nominal capacity (mAh) charging temperature (℃) discharging temperature (℃) charging current (A) discharging current (A)
ICR18650 (ternary) 3.7V 2200mAh 0~45 ℃ -40 ℃~+60 ℃ 2.2A (room temperature 1C) 10A (room temperature 5C)
ICR18650 (ternary) 3.7V 2500mAh 0~45 ℃ -40 ℃~+60 ℃ 2.5A (room temperature 1C) 25A (room temperature 10C)
ICR18650 (ternary) 3.7V 3000mAh 0~45 ℃ -40 ℃~+60 ℃ 3.0A (room temperature 1C 15A (room temperature 5C))
ICR21700 (ternary) 3.7V 4000mAh 0~45 ℃ -40 ℃~+60 ℃ 4.0A (room temperature 1C) 40A (room temperature 10C)
NCR18650B (ternary) 3.6V 3350mAh 0~45 ℃ -20~60 ℃ 1.625A 4.875A
INR18650-30Q (ternary) 3.6V 3000mAh 0~45 ℃ -20~75 ℃ 0.5C 15A
IFR26650 (Lithium Iron Phosphate) 3.2V 3200mAh -20 ℃~+45 ℃ -40 ℃~+60 ℃ 3.2A (1C at room temperature) 10A (3C at room temperature)
IFR32700 (Lithium Iron Phosphate) 3.2V 5000mAh -20 ℃~+45 ℃ -40 ℃~+60 ℃ 5.0A (1C at room temperature) 25A (5C at room temperature)
IFR26650 E3400 (Lithium Iron Phosphate) 3.2V 3400mAh 0~60 ℃ -10~60 ℃ 2.0V 10.2A


1、 What is cylindrical lithium battery?


1. Definition of cylindrical battery


Cylindrical lithium batteries are divided into different systems such as lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, cobalt manganese hybrid, and ternary materials. The outer shell is divided into two types: steel shell and polymer. Different material systems have different advantages for batteries. At present, steel shell cylindrical lithium iron phosphate batteries are mainly used for cylinders. These batteries are characterized by high capacity, high output voltage, good charge discharge cycle performance, stable output voltage, high current discharge, stable electrochemical performance, safe use, wide working temperature range, and environmental friendliness. They are widely used in solar lamps, lawn lamps, backup energy, power tools, and toy models.


2. Cylindrical battery structure


A typical cylindrical battery structure includes: shell, cap, positive electrode, negative electrode, separator, electrolyte, PTC element, gasket, safety valve, etc. The general battery shell is the negative electrode of the battery, the cap is the positive electrode of the battery, and the battery shell is made of nickel plated steel plate.


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3. Advantages of cylindrical lithium batteries


Compared with soft pack and square lithium batteries, cylindrical lithium batteries have the longest development time, higher standardization, more mature technology, high yield rate, and low cost.


·Mature production process, low PACK cost, high yield of battery products, and good heat dissipation performance

·Cylindrical batteries have formed a series of internationally unified standard specifications and models, with mature technology suitable for large-scale continuous production.

·The cylinder has a larger specific surface area and better heat dissipation effect.

·Cylindrical batteries are generally sealed batteries, and there are no maintenance issues during use.

·The battery casing has high voltage resistance, and there will be no phenomena such as square or flexible packaging battery expansion during use.


4. Cylindrical battery positive electrode material


At present, the mainstream commercial cylindrical battery cathode materials mainly include lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), ternary (NMC), lithium iron phosphate (LiFePO4), etc. Different material systems have different characteristics for batteries, and the comparison is as follows:



Project Lithium Cobalt Oxide Lithium Nickel Cobalt Manganese Ternary (LiNiCoMnO2) Lithium Manganese Oxide (LiMn2O4) Lithium Iron Phosphate (LiFePO4)
Tap density (g/cm3) (LiCoO2) 2.0~2.3 2.2~2.4 1.0~1.4
Specific surface area (m2/g) 2.8-3.0 0.2-0.4 0.4-0.8 12-20
Gram capacity (mAh/g) 0.4-0.6 140-180 90-100 130-140
Voltage platform (V) 135~140 3.5 3.8 3.2
Cycle performance 3.7 ≥ 500 times ≥ 300 times ≥ 2000 times
Transition metals ≥ 500 times, poor, rich, very rich
Poor raw material costs, high and low prices
Highly environmentally friendly, nickel and cobalt are non-toxic and non-toxic
Good safety performance with good cobalt content, excellent performance
Applicable fields: small battery/small power battery, low-cost battery power battery/ultra large capacity power supply
Advantages: Small and medium-sized batteries have stable electrochemical performance, good cycling performance, abundant manganese resources, low price, good safety performance, high safety, environmental protection, and long lifespan
Disadvantages: "Stable charging and discharging, simple production process, expensive cobalt price, low cycle life" Cobalt is expensive, low energy density, poor electrolyte compatibility, poor low-temperature performance, and low discharge voltage



5. Cylindrical battery negative electrode material


There are approximately six types of negative electrode materials for cylindrical batteries: carbon negative electrode materials, alloy negative electrode materials, tin based negative electrode materials, lithium containing transition metal nitride negative electrode materials, nanoscale materials, and nanoscale negative electrode materials.


·Carbon nano level negative electrode materials: Currently, the negative electrode materials used in lithium-ion batteries are mostly carbon materials, such as artificial graphite, natural graphite, intermediate phase carbon microspheres, petroleum coke, carbon fiber, pyrolytic resin carbon, etc.

·Alloy based negative electrode materials: including tin based alloys, silicon-based alloys, germanium based alloys, aluminum based alloys, antimony based alloys, magnesium based alloys, and other alloys. Currently, there are no commercial products available.

·Tin based negative electrode materials: Tin based negative electrode materials can be divided into two types: tin oxides and tin based composite oxides. Oxide refers to the oxide of various valence states of tin metal. There are currently no commercial products available.

·There are currently no commercial products for lithium containing transition metal nitride negative electrode materials.

·Nano scale materials: carbon nanotubes, nano alloy materials.

·Nano negative electrode material: nano oxide material


2、 Cylindrical lithium battery cells


1. Cylindrical lithium-ion battery cell brand


Cylindrical lithium batteries are quite popular among lithium battery companies in Japan and South Korea, and there are also considerable enterprises in China that produce cylindrical lithium batteries. The earliest cylindrical lithium battery was invented by the Japanese company SONY in 1992.


Famous cylindrical lithium-ion battery brands: Sony, Panasonic, Sanyo, Samsung LG、 Wanxiang A123, Bick, Lishen, etc.


2. Types of cylindrical lithium-ion batteries


Cylindrical lithium-ion batteries are usually represented by five digits. Starting from the left, the first and second digits refer to the battery diameter, the third and fourth digits refer to the battery height, and the fifth digit represents a circle. There are many types of cylindrical lithium batteries, among which the more common ones are 10400, 14500, 16340, 18650, 21700, 26650, 32650, etc.


① 10440 battery


The 10440 battery is a lithium battery with a diameter of 10mm and a height of 44mm, which is the same size as the commonly referred to "No. 7 battery". This type of battery has a very small capacity, only a few hundred mAh, and is mainly used in mini electronic products. For example, flashlights, mini speakers, amplifiers, etc.


② 14500 battery


The 14500 battery is a lithium battery with a diameter of 14mm and a height of 50mm. This type of battery is generally 3.7V or 3.2V, with a nominal capacity of slightly smaller than the 10440 battery, usually 1600mAh. It has superior discharge performance and is mainly used in consumer electronics, such as wireless speakers, electric toys, digital cameras, etc.


③ 16340 battery


The 16340 battery is a lithium battery with a diameter of 16mm and a height of 34mm. Due to its shorter height and not very small capacity, it is often used in high-intensity flashlights, LED flashlights, headlights, laser lights, lighting fixtures, etc.


④ 18650 battery


18650 battery is a lithium battery with a diameter of 18mm and a height of 65mm. Its biggest feature is that it has a very high energy density, almost reaching 170 watt hours/kilogram. Therefore, this type of battery is a cost-effective battery. Most of the batteries we often see are mature lithium batteries with good system quality stability. It is widely used in battery capacity applications of about 10 kilowatt hours, such as in small appliances such as mobile phones and laptops.


⑤ 21700 battery


The 21700 battery is a lithium battery with a diameter of 21mm and a height of 70mm. Due to its increased volume, space utilization efficiency, and improved energy density of individual cells and systems, its volumetric energy density is much higher than that of the 18650 battery. It is widely used in digital, electric vehicles, balance bikes, solar powered lithium battery street lights, LED lights, power tools, etc.


⑥ 26650 battery


The 26650 battery is a lithium battery with a diameter of 26mm and a height of 65mm. It has a nominal voltage of 3.2V and a nominal capacity of 3200mAh. This type of battery has excellent capacity and high consistency, and has gradually become a trend to replace the 18650 battery. Many products in the field of power batteries will also gradually favor it.


⑦ 32650 battery


The 32650 battery is a lithium battery with a diameter of 32mm and a height of 65mm. This type of battery has strong continuous discharge ability, making it suitable for electric toys, backup power sources, UPS batteries, wind power generation systems, and wind solar complementary power generation systems.


3、 Development of cylindrical lithium battery market


The technological progress of cylindrical lithium-ion batteries mainly comes from innovative research and application of key battery materials. Through the development of new materials, battery performance, quality, cost reduction, and safety can be further improved. To meet the requirements of downstream applications for increasing the specific energy of batteries, on the one hand, high specific capacity materials can be used, and on the other hand, high-voltage materials can be used by increasing the charging voltage.


The cylindrical lithium-ion battery has developed from 14500 to Tesla 21700. In the near to medium term, while optimizing the existing system lithium-ion power battery technology to meet the needs of large-scale development of new energy vehicles, the focus is on developing new lithium-ion power batteries to improve their safety, consistency, and lifespan, and to simultaneously carry out forward-looking research and development of new system power batteries.


In order to promote the medium to long term development of cylindrical lithium-ion batteries, while continuously optimizing and improving new lithium-ion power batteries, we will focus on researching and developing new system power batteries, significantly improving specific energy, significantly reducing costs, and achieving practical and large-scale applications of new system power batteries.


4、 Comparison between cylindrical lithium batteries and square lithium batteries


1. Battery shape: Square size can be designed arbitrarily, while cylindrical batteries cannot be compared.


2. Rate characteristics: Due to the process limitations of welding multipole ears in cylindrical batteries, the rate characteristics are slightly inferior to those of square multipole ear batteries.


3. Discharge platform: Lithium batteries using the same positive and negative electrode materials and electrolyte should theoretically have the same discharge platform, but the discharge platform inside square lithium batteries is slightly higher.


4. Product quality: The manufacturing process of cylindrical batteries is relatively mature, and the probability of secondary slitting defects in the pole pieces is low. In addition, the maturity and automation level of the winding process are relatively high. Currently, the stacking process is still semi manual, which has a negative impact on battery quality.


5. Pole ear welding: Cylindrical battery pole ears are easier to weld than square lithium batteries; Square lithium batteries are prone to virtual soldering, which can affect battery quality.


6. PACK grouping: Cylindrical batteries have easier to use characteristics, so PACK technology is simple and has good heat dissipation effect; When packing square lithium batteries, it is necessary to solve the problem of heat dissipation.


7. Structural characteristics: The chemical activity at the corners of square lithium batteries is poor, and the energy density of the battery is prone to decay after long-term use, resulting in a shorter battery life.


5、 Comparison between cylindrical lithium batteries and soft pack lithium batteries


1. Soft pack batteries have good safety performance. Soft pack batteries are packaged with aluminum-plastic film in the structure. When safety issues occur, soft pack batteries generally burst and crack, unlike steel or aluminum shell cells that explode; It is superior to cylindrical lithium batteries in terms of safety performance.


2. Soft pack batteries are relatively lightweight, with a weight 40% lighter than steel shell lithium batteries of the same capacity and 20% lighter than cylindrical aluminum shell lithium batteries; Low internal resistance, the internal resistance of soft pack batteries is smaller than that of lithium batteries, which can greatly reduce the battery's self consumption;


3. Soft pack batteries have good cycling performance and a longer cycle life, with a decay rate of 4% to 7% less than cylindrical aluminum shell batteries after 100 cycles;


4. The design of soft pack batteries is relatively flexible, with adjustable shapes and the ability to be thinner. They can be customized according to customer needs and new cell models can be developed. However, cylindrical lithium batteries do not have this condition.


5. The shortcomings of soft pack batteries compared to cylindrical lithium batteries are poor consistency, high cost, and easy leakage. The high cost can be solved through large-scale production, while the leakage can be resolved by improving the quality of aluminum-plastic film.