Do you know these knowledge of cylindrical lithium batteries?

Cylindrical lithium batteries are divided into different systems of lithium iron phosphate, lithium cobaltate, lithium manganate, mixed cobalt and manganese, and ternary materials. The shell is divided into two types: steel shell and polymer. Different material systems have different advantages.

Lithium battery cylindrical model list

A. What is a cylindrical lithium battery?

1、Definition of cylindrical battery

Cylindrical lithium batteries are divided into different systems of lithium iron phosphate, lithium cobaltate, lithium manganate, mixed cobalt and manganese, and ternary materials. The shell is divided into two types: steel shell and polymer. Different material systems have different advantages. At present, the cylinder is mainly steel shell cylindrical lithium iron phosphate battery. The performance of this battery is high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, high current discharge, stable electrochemical performance, safe use, wide working temperature range, and environmentally friendly. It is widely used in solar lamps, lawn lamps, backup energy sources, electric tools, and toy models.

2、Cylindrical cell structure

A typical cylindrical battery has a structure including a case, a cap, a positive electrode, a negative electrode, a separator, an electrolyte, a PTC element, a gasket, a safety valve, etc. Generally, the 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.

3. Advantages of cylindrical lithium batteries

Compared with polymer and square lithium battery, cylindrical lithium battery has the longest development time, higher degree of standardization, more mature technology, high yield and low cost.

• Mature production process, low PACK cost, high yield of battery products, good heat dissipation performance
• Cylindrical batteries have formed a series of internationally unified standard specifications and models, mature technology, suitable for large-scale continuous production.
• The specific surface area of the cylinder is large, and the heat dissipation effect is good.
• Cylindrical batteries are generally sealed batteries, and there are no maintenance problems during use.
• The battery shell has high pressure resistance, and there will be no phenomena such as square or soft package battery expansion during use.

4. Cylindrical battery cathode material

At present, the mainstream commercial cylindrical battery cathode materials are mainly lithium cobalt oxide (LiCoO2), lithium manganate (LiMn2O4), ternary (NMC), lithium iron phosphate (LiFePO4), etc., different material system batteries have different characteristics, compared as follows:

5、Anode materials for cylindrical batteries

Cylindrical battery anode materials are roughly divided into six types: carbon anode materials, alloy anode materials, tin-based anode materials, lithium-containing transition metal nitride anode materials, nanoscale materials, and nano-anode materials.

• Carbon nano-materials anode materials: At present, the anode materials that have been actually used in lithium-ion batteries are basically carbon materials, such as artificial graphite, natural graphite, mesophase carbon microspheres, petroleum coke, carbon fiber, pyrolytic resin carbon, etc.
• Alloy-based anode materials: including tin-based alloys, silicon-based alloys, germanium-based alloys, aluminum-based alloys, antimony-based alloys, magnesium-based alloys and other alloys, and there are currently no commercial products.
• Tin-based anode materials: Tin-based anode materials can be divided into tin oxides and tin-based composite oxides. The oxide refers to an oxide of metal tin in various valence states. There are currently no commercial products.
• Lithium-containing transition metal nitride anode materials, there is no commercial product at present.
• Nano-scale materials: carbon nanotubes, nano-alloy materials.
• Nano anode materials: nano oxide materials

B. Cylindrical lithium battery cell

1. Cylindrical lithium ion battery core brand

Cylindrical lithium batteries are more popular in Japan and South Korea, and there are also large-scale enterprises in China that produce cylindrical lithium batteries. The earliest cylindrical lithium battery was invented by Japan's SONY company in 1992.

Well-known cylindrical lithium ion cell brands: Sony, Panasonic, Sanyo, Samsung, LG, Wanxiang A123, Bick, Lishen, CATL, Gove, EVE, etc.

2. Types of cylindrical lithium ion cells

Cylindrical lithium-ion battery core is usually represented by the 5 digit. From the left, the first and second digits refer to the diameter of the battery, the third and 4 digits refer to the height of the battery, and the fifth digit represents the circle. There are many types of cylindrical lithium batteries, the more common ones are 10400, 14500, 16340, 18650, 21700, 26650, 32650, 32140, 33140, etc.

① 10440 battery

10440 battery is a kind of lithium battery with a diameter of 10mm and a height of 44mm. It is the same as the size we often call "No.7 battery". The battery capacity is generally very small, only a few hundred mAh, and is mainly used in mini electronic products. For example, flashlights, mini speakers, loudspeakers, etc.

② 14500 battery

14500 battery is a kind of lithium battery with a diameter of 14mm and a height of 50mm. This battery is generally 3.7V or 3.2V. The nominal capacity is relatively small, a little larger than 10440 batteries, generally 1600mAh, with superior discharge performance. The main application areas are consumer electronics, such as wireless audio, electric toys, digital cameras, etc.

③ 16340 battery

16340 battery is a kind of lithium battery with a diameter of 16mm and a height of 34mm. This kind of battery is often used in strong flashlights, LED flashlights, headlights, laser lights, lighting lamps, etc. due to its shorter height and not very small capacity.

④ 18650 battery

18650 battery is a kind of lithium battery with a diameter of 18mm and a height of 65mm. Its greatest feature is that it has a very high energy density, reaching almost 170 WHr/kg. Therefore, this kind of battery is a battery with good cost performance. Most of the batteries we often see at ordinary times are this kind of battery, because it is a relatively mature lithium battery with good quality stability in all aspects and is widely applicable to battery capacity occasions around 10 kW hours, for example, on small appliances such as mobile phones and laptops.

⑤ 21700 battery

21700 battery is a kind of lithium battery with a diameter of 21mm and a height of 70mm. Because its volume increases, the space utilization rate becomes larger, the energy density of the battery cell and the system can be improved, and its volume energy density is much higher than that of the 18650 battery. It is widely used in digital, electric vehicles, balance vehicles, solar energy lithium battery street lights, LED lights, electric tools, etc.

⑥ 26650 battery

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

⑦ 32650 battery

32650 battery is a kind of lithium battery with a diameter of 32mm and a height of 65mm. This kind of battery has a strong continuous discharge capacity, so it is more suitable for electric toys, backup power supply, ups battery, wind power generation system and wind-solar complementary power generation system.

⑧ 32140 battery

32140 all-pole large cylindrical battery is the high energy density, low cost power battery. The use of full-pole ear structure solves the problem of insufficient rate performance of traditional cylindrical batteries, and has a broad prospect in the future new energy vehicle market.

⑨ETC

C. cylindrical lithium battery market development

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

In the development of cylindrical lithium-ion batteries in the near and medium term, while optimizing the existing system lithium-ion power battery technology to meet the needs of the large-scale development of new energy vehicles, focusing on the development of new lithium-ion power batteries, improving their safety, consistency and Life and other key technologies, simultaneously carry out forward-looking research and development of new system power batteries.

For the medium-and long-term development of cylindrical lithium-ion batteries, while continuously optimizing and upgrading new lithium-ion power batteries, the focus is on the development of new system power batteries, significantly improving the specific energy, significantly reducing costs, and realizing the practical and large-scale application of new system power batteries.

D. cylindrical lithium battery and square lithium battery comparison

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

2. Rate characteristics: cylindrical battery welding multi-pole process limitations, rate characteristics slightly worse than the square multi-pole battery.

3. Discharge platform: lithium batteries using the same positive and negative materials and electrolyte, theoretically speaking, the discharge platform should be the same, but the discharge platform in the square lithium battery is slightly higher.

4. Product quality: The manufacturing process of the cylindrical battery is relatively mature, the probability of the pole piece having the second cutting defect is low, and the maturity and automation degree of the winding process are relatively high.

5. ear welding: cylindrical battery ear is easier to weld than square lithium battery; square lithium battery is easy to produce virtual welding to affect the quality of the battery.

6.PACK group: cylindrical batteries are easier to use, so PACK technology is simple and the heat dissipation effect is good; square lithium battery PACK should solve the problem of heat dissipation.

7. structural features: square lithium battery corner of poor chemical activity, long-term use of the battery energy density is easy to decay, shorter battery life.

E. cylindrical lithium battery and polymer lithium battery comparison

1. The polymer battery has good safety performance. The polymer battery is packaged with aluminum-plastic film in structure. When a safety problem occurs, the polymer battery will generally blow up and crack, instead of exploding like a steel shell or aluminum shell battery. The safety performance is superior to cylindrical lithium batteries.

2. The weight of the polymer battery is relatively light. The weight of the polymer battery is 40% lighter than that of the steel-shell lithium battery with the same capacity and 20% lighter than that of the cylindrical aluminum-shell lithium battery. The internal resistance is small, and the internal resistance of the polymer battery is smaller than that of the lithium battery, which can greatly reduce the self-consumption of the battery;

3. The polymer battery has good cycle performance, the cycle life of the polymer battery is longer, and the 100 cycle attenuation is 4% ~ 7% less than that of the cylindrical aluminum shell battery;

4. The soft pack battery design is more flexible, the shape can be changed in any shape, can be thinner, can be customized according to customer needs, the development of new cell models. The cylindrical lithium battery does not have this condition.

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

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