How to Choose 21700 Type Li-ion Cells?

07 Apr.,2025

 

A General Understanding Of Lithium-Ion Batteries-Tycorun ...

1.What is the battery?

The battery is another lithium-ion battery, and the number denotes the cell size. It comes in 21mm in diameter and 70mm in length. The  battery comes with an ampere power between mAh and mAh.

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While compared to lithium batteries, it is more significant in length and diameter. The lithium ion battery has a technical design to offer a voltage range between 2.5v to 4.2v and a charging voltage of 4.2v. However, the nominal voltage of battery  will be 3.7v. The battery requires about 5 hours for a full recharge, but the charging time may vary subject to the charger voltage, amperage, and battery type.

2.How much does a battery cost?

The price of a lithium ion battery or any other battery depends on various factors. The price may vary depending on the brand's popularity, charging and discharging cycles, battery chemistry, power capacity, protective features, etc. On a general perception, the cost of a battery is between $6.95 to $28.95.

3.What is battery used for?

Like lithium batteries, cells also power many electronic and luminary devices. These batteries are used on flashlights, and electric vehicles. Since these batteries are rechargeable, they can use in all devices that come with built-in rechargers and need a voltage requirement of 3.2/3.7v.

4.How long does a battery take to charge?

A battery pack can typically charge within 4 hours; however, the charging time depends on the charger and battery capacity. You can quickly recharge a battery with a fast recharger than with a slow recharger.

These statistics show that you must use a recharger with a higher capacity for quick recharging.

The lithium ion battery comes with -mAh, so you should use a charger matching the battery capacity for fast charging. If you use a 2A charger to recharge a mAh battery, it will take about 2 hours to complete the charging. Similarly, if you use a 1A charger, the recharging timing will be approximately 3-4 hours.

5.How much does a battery weight?

The weight of a battery will be between 55gms to 75gms, depending on the technology and capacity.

6.Are the same as ?

Both and cells are not the same. Their physical dimension is different to one another. When comes with 18mm diameter and 65mm length, the battery comes with 21mm diameter and 70mm height. The last digit '0' denotes its cylindrical shape. Both are identical in shape, i.e., both are cylindrical. However, is slightly bigger than ; hence,when the battery type is the same, can offer more power than batteries.

On the capacity segment, offers mAh to mAh, while offers mAh to mAh. Both can provide 3.7v output, but the output current of lithium-ion battery is more than 36Amps, but battery offers more than 25Amps.

lithium ion battery has 35% more cell capacity than batteries. Similarly, the energy density of a battery also shows an increment of 20%. As per the data released by Tesla, the energy density of was 250Wh/kg, but when they started using batter, the energy density registered as 300Wh/kg. The energy density of battery in volumetric terms stands 20% higher than batteries.

The volume of a battery is cubic mm, and  battery is cu mm, which means the latter has ~47% more volume. If we consider 10-12% of the volume space used to incorporate the protective features, the batteries still have room to produce more power. So, considering all these factors, and batteries are not the same. Since  battery has extended battery life and high output, it has a better edge over batteries.

7.Which battery is better vs ?

In the lithium battery segment, bigger batteries have high power delivery advantage than smaller batteries. Bigger batteries will have extended battery life than smaller batteries and a better amp rating. While comparing and battery, both have the same length, but one has a 20mm diameter, and the other has a 21mm diameter. Even though both have no considerable difference, batteries shall have a better amp rating and can discharge 30-45 amps continuously.

8.Can I Use batteries in my vape?

Yes, you can use lithium ion batteries in the vaping device. These batteries are the upgraded version of and batteries. The lithium ion batteries are larger than and , hence can deliver more amps continuously. Many companies are using lithium ion batteries for their vaping devices.

9.Are all batteries rechargeable?

The lithium ion batteries are rechargeable. Because of this, it has been used in electric vehicles, vaping devices, flashlights, and many other devices that require power to operate.The beauty of batteries is their size and power delivery capacity. Let us examine a projected situation to understand the convenience of using lithium ion batteries instead of other batteries.

Suppose you want to run a BTU cooling capacity air conditioner that consumes about watts per hour; you can run the air conditioner for one hour by using a battery pack of 74 cells. But to accomplish this task, you must use a lithium ion battery with 3.7v and mAh that can store 3aH to 5aH power and store about 11–18-watt hours.

①Limits of Recharging

All lithium-ion batteries are rechargeable, and they will have a limited recharge cycle. Due to chemical degradation and oxidation, the battery recharging cycle gets degraded over a period. All batteries do have these issues. The lithium ion batteries feature - cycles.

② Recharge Frequency of Batteries

Lithium batteries come with a rechargeable feature, and a battery will have - recharge cycles. So, your recharging pattern will decide the battery life. When your battery voltage reduces to 3v from 3.7v, you can put it for recharge. Frequent recharging may reduce the life of the battery, but not so for lithium-ion batteries. Because lithium-ion batteries have no memory effect.. Therefore, instead of going for a regular recharge, check the voltage level, and if it drops below 3v, do a recharge. If a lithium-ion battery voltage drip down to 2.5v, the battery may lock by itself, making it impossible to recharge using an ordinary recharger.

10.Which battery is best?(samsung,lg,panasonic,sony, which is best? )

In the best battery segment, Panasonic stands top. The mAh battery shows a continuous discharge rating of 30A and a nominal voltage of 3.7v. Because of the constant high voltage delivery, it reduces battery usage. The rechargeable battery offers + life cycles, and it can deliver 75 watts. It's high energy density minimizes the battery weight and size. These batteries are famous for their efficiency and can use for an extended period. The battery does not have any memory accumulation issues; hence you can always get a full charge after every recharge.

The LG50 lithium-ion battery is available with an energy capacity of mAh with a nominal voltage of 3.6v is our 2nd preference. The battery can offer a full charge voltage of 4.2v with a variation of +/- 0.05v. With a maximum continuous discharge rate of 7.27A and discharge cut-off voltage of 2.50v, this is an ideal battery for electronic devices that consume low power for an extended period. The battery comes with 500 recharge cycles, but you can recharge it + cycles if appropriately used. It is an unprotected battery, so it is best to use a protected battery management system.
Our third preference is the Sony lithium-ion battery USVTC6A which comes with mAh. It can offer a 40A continuous discharge at a 3.6v nominal voltage and a maximum of 4.2v. It is rechargeable but unprotected. You should use it with a protected battery pack. With a 9A recharger, it can recharge quickly and can let you have 500+ recharge cycles. It sells for US$9 per piece, and with a 3-year shelf life, it is a good option for using high-drain electronic devices that require minimum discharge rates.

Among various lithium ion batteries, Samsung 40T (Lithium Manganese Nickel -LiNiMnCoO2) has better market acceptance than the rest of the competitors and is one of the famous brands. The battery comes with mAh and can deliver 25A continuous power discharge with a maximum discharge current of 35A or 45A with a temperature cut off mark at 80°C. It can let you use 75W continuously without any break for an extended period. It comes with 250+ cycles with a 6A charger and can recharge more than 500 times if appropriately recharged. The battery’s market price is about $7.50 per unit.

Model

Size

Chemistry

Voltage

Capacity

Discharge

Cycles

Panasonic

21x70

INR

3.56v-3.6v

mAh

15A-20A

+

LG50

21x70

INR

3.63v

mAh

7.27A

+

Sony VTC6A

21x70

INR

3.6v-3.7v

mAh

30A

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500+

Samsung 40T

21x70

INR

3.6v-4.2v

mAh

35A

250+

11.Dose Tesla use battery

①Are the same as ?

Previously Tesla has been using lithium batteries to power their electric vehicles. Now they are using cells for new model electric vehicles. As per the data released by Tesla, the energy density of lithium ion batteries is 20% more than batteries. The increased energy density is mainly attributed to the size and new battery chemistry.

Another critical aspect of batteries compared to batteries are their price. As per the data released by Tesla, the cost is less by 9% compared to batteries, which was about $185. The cost of batteries stands around $170. When the system costs about $171 per MH, the will be 9% less and may touch about $155 per Zhn.As per industry experts, the component and weight can also be reduced by 10% by using lithium-ion batteries rather than batteries. So, if the weight of the battery is less, that will eventually have an advantage over the energy density of the vehicle.

② Tesla battery

Tesla has been using batteries for their S and X model vehicles, but for the new Model 3 cars, they are using batteries. These batteries have 46% more cell volume than batteries. Also, as per a report released by Tesla, they are 15% more energy efficient. They have a cell capacity of 21.275Wh and show an energy density of ~877.5Wh/L.

12. Lithium-ion Batteries - Final thoughts

The lithium ion batteries are the best-preferred option for electronic devices and electric vehicles because it comes with ~35% more cell capacity and hence can produce 20% more energy than batteries. These batteries show moderate resistance to temperature fluctuations and short circuit issues. So, they are ideal for devices that require low power drain for an extended period.

The lithium ion batteries are rechargeable, and by using quick rechargers, you can get the battery charged to the required voltage level. Another highlighted feature of the best lithium on batteries is their nominal voltage discharge rates. They can deliver 3.7v on average and can deliver a maximum of 4.2v.

However, while purchasing the best lithium-ion battery, you need to check its mAh and discharge rates, marked as C-rate. If the discharge is too high, then there is no point in having a battery with high capacity. On average, lithium-ion batteries will have a power capacity of to mAh, but they should also have a corresponding slow discharge rate.

When the discharge rate is very high, it will drain your battery quickly. So, the best way to ensure the discharge rate is whether the C-rate matches the power capacity. If the power capacity is mAh, then the C-rate should be 30A, and if the power capacity is mAh, then the C-rate should be 50A. Any discharge rate more than the corresponding power capacity will fail to give the expected result. Similarly, check the battery's nominal average voltage level.

Any  lithium ion battery with a nominal voltage of 3v is good if it matches your device’s requirement. So, you must check the nominal voltage requirement before deciding on the battery and make sure the battery can match the voltage requirement with the nominal voltage offered by the battery.All cells may look the same in their physical appearance because of their size, 21mm diameter and 70mm length. However, their internal chemistry will be different from one another; their power output, continuous discharge rate, maximum power capacity, and voltage may vary according to the brand and model. Some batteries have protected features, and some don't have that feature. Therefore, you must select battery, matching the device's voltage and power requirement; otherwise, it may damage your device.

Your Ultimate Guide to Explore the Battery

In this article, we’ll take a deep dive into the features, specifications, and typical applications of batteries. Whether you are a consumer, a manufacturer, or just someone interested in energy storage solutions, this guide will provide you with all the information you need.

Part 1. What is a Battery?

A battery is a type of lithium-ion rechargeable cell. The name “” refers to its physical dimensions: it has a 21mm diameter and 70mm length. This makes it larger than the popular battery, which measures 18mm x 65mm. While the may seem just slightly bigger, its larger size provides substantial benefits in terms of energy storage, power output, and overall performance.

The increased size of the battery means that it can hold significantly more energy compared to its smaller cousins. This results in a longer battery life per charge and improved efficiency in many high-demand devices.

One of the standout features of the is its higher capacity and energy density compared to smaller batteries. This allows it to power larger devices, such as electric vehicles and solar energy storage systems, with more reliable performance and fewer recharges.

Part 2. battery size

As mentioned earlier, the battery is 21mm in diameter and 70mm in length. This cylindrical shape is the same as other lithium-ion cells, but the extra length and diameter allow for greater energy storage. To put it into perspective, a typical battery can store 5,000mAh of charge, whereas the more common battery typically holds between 2,500mAh to 3,500mAh.

This size increase directly correlates with performance improvements. Larger batteries can deliver higher discharge rates, which means that devices using batteries can consume energy at a faster rate without significantly reducing the battery’s lifespan.

It’s also worth noting that the battery is widely used in applications that require both high energy density and compact size. Its ability to deliver more power with less weight makes it perfect for energy-demanding applications like electric vehicles and power tools.

Part 3. Chemistry and structure

The chemistry and internal structure of a battery can vary depending on the manufacturer and its intended application. However, most cells are based on lithium-ion (Li-ion) technology, which is widely used across many types of rechargeable batteries due to its excellent energy density and long lifespan.

There are several types of lithium-ion chemistries that could be used within the format:

  • Lithium Cobalt Oxide (LCO): High energy density but lower safety and lifespan.
  • Lithium Iron Phosphate (LiFePO4): Safer with longer cycles but lower energy density.
  • Nickel Manganese Cobalt (NCM): Provides a balance of energy density, cost, and safety.

The internal structure of the battery consists of several key components:

  • Anode: Usually made from graphite, this component stores the lithium ions during the discharge process.
  • Cathode: Often made from lithium cobalt oxide or similar materials, it releases lithium ions during discharge.
  • Electrolyte: A liquid or gel-like substance that allows the flow of lithium ions between the anode and cathode.
  • Separator: A non-conductive layer that prevents the anode and cathode from coming into direct contact, thus avoiding short circuits.

While batteries come in different chemistries, they all share a similar basic structure that allows them to provide excellent performance in a wide range of applications.

Part 4. Voltage

The voltage of a battery typically varies between 3.6V to 3.7V when it’s in use. However, the voltage will fluctuate depending on its state of charge:

  • Full Charge: The voltage will be around 4.2V.
  • Nominal Voltage: The 3.7V is the average voltage at which most of the battery’s charge is used.
  • Discharge Cutoff: Below 3.0V, the battery will lose its charge completely and may suffer permanent damage if discharged beyond this point.

The nominal voltage of batteries makes them compatible with most devices that use lithium-ion cells, including electric vehicles, flashlights, and drones. It’s important to understand these voltage ranges when selecting chargers and other accessories.

Part 5. Weight

The weight of a battery typically ranges from 50 to 70 grams, depending on the exact chemistry and the manufacturer. While this weight is heavier than that of smaller batteries, the trade-off is the higher capacity and energy density of the .

For example, an battery might weigh only about 40-50 grams, but because the holds more power, it’s heavier. This makes the battery ideal for use in larger devices that need extended run times, like electric vehicles or power tools, where every extra gram is justified by the performance improvements.

Part 6. Energy Density

One of the key advantages of batteries is their energy density. Typically, batteries have an energy density ranging from 250 Wh/kg to 300 Wh/kg, depending on the chemistry used. This is a notable improvement compared to batteries, which usually offer around 180 Wh/kg to 250 Wh/kg.

The higher energy density of the battery allows for longer use times between charges. It also makes these batteries ideal for devices that require both power and portability. For instance, electric vehicles can use cells to store more energy in less space, resulting in longer driving ranges without increasing the size of the battery pack.

Part 7. cell and pack(battery)

A cell refers to an individual battery unit, while a pack is a configuration of multiple cells connected in series or parallel. The pack is typically what you find in larger, power-hungry devices like electric vehicles or solar energy storage systems.

  • Series Connection: This method connects cells end to end to increase the total voltage. For instance, a 3.7V cell connected in series with another would provide a 7.4V pack.
  • Parallel Connection: Cells are connected side by side to increase the overall capacity (mAh). This increases the total energy storage without affecting the voltage.
  • Series-Parallel Combination: This is the most common method, where cells are arranged in both series and parallel to achieve the desired voltage and capacity.

To safely operate a pack, it’s crucial to use a Battery Management System (BMS). The BMS monitors the voltage, temperature, and charge cycles of each individual cell within the pack to ensure safe operation.

Part 8. Typical applications

The battery is used in a variety of high-demand applications, including:

  • Electric Vehicles (EVs): Due to their high energy density and longevity, batteries are being adopted by companies like Tesla for use in their vehicles. These batteries help provide longer driving ranges between charges.
  • Power Tools: Companies like DeWalt and Makita use cells in their cordless power tools for improved runtime and power output.
  • Flashlights: High-performance flashlights use cells for extended run times, allowing users to operate lights for hours on a single charge.
  • E-cigarettes (Vaping): The battery is favored in high-wattage e-cigarettes due to its ability to deliver high current.
  • Drones: Drones that require extended flight times and higher power output rely on batteries for their long-lasting power.

Part 9. battery vs

The most significant difference between the and batteries is their size and capacity. The is larger (21mm x 70mm) compared to the (18mm x 65mm), and this size difference allows the to store more energy.

  • Capacity: The typically holds mAh or more, while the generally maxes out around mAh.
  • Energy Density: batteries have a higher energy density, meaning they can deliver more power for a longer period of time, making them a better choice for high-demand applications.

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vs Battery: What Difference is between them?

Part 10. How long does a battery last?

The lifespan of a battery is generally measured in charge cycles, which refers to the number of times the battery can be charged and discharged before it starts to lose capacity. On average, a battery can last between 500 to charge cycles, depending on its chemistry, usage, and maintenance.

To maximize the lifespan of your battery, avoid deep discharges (below 20% charge) and overcharging (above 100%). Proper storage at moderate temperatures also helps ensure a long lifespan.

Part 11. Charger, charging and maintenance

When charging your battery, make sure to use a compatible charger designed for lithium-ion batteries. A Battery Management System (BMS) is often required for safe charging, especially in battery packs.

Charging Tips:

  • Never leave your battery charging unattended.
  • Use a charger with overcharge protection to prevent battery damage.
  • Store your battery in a cool, dry place to avoid overheating.

Maintenance Tips:

  • Check for signs of wear, such as swelling or leakage.
  • Regularly clean the battery terminals to ensure proper connections.
  • If the battery is not used for an extended period, store it at 40-60% charge.

Part 12. Ufine battery

Ufine, a leading Chinese manufacturer of lithium batteries. They’re known for customizing battery shapes, sizes, capacities, and voltages. Whether you need lithium polymer, cylindrical, or LiFePO4 batteries, Ufine has you covered.

Their batteries are reliable and high-quality, catering to various power needs. If you’re looking for a battery that fits your specific requirements, Ufine is a great option to consider. They combine innovation with practicality, ensuring you get the best power solution for your devices.

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