What is 3.2v 21700 Lithium Battery and Why Do We Use Them?

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.

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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.

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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.

Yichun Topwell Power Co., Ltd (Trademark:TWE) established in , is a high-tech enterprise focusing on the R&D, production and sales of lithium polymer batteries, lithium ion batteries, lithium iron phosphate batteries, and lithium thionyl chloride batteries. Products are widely used in consumer electronics, Internet of Things, smart home, medical, vehicle, home and outdoor energy storage, and have obtained CE, RoHS, Reach, UN38.3, IEC, CB, UL, MSDS certifications, etc.

Topwell moves on by providing reliable, efficient and intelligent battery solutions to meet different energy needs. We have efficient engineering, production and quality management teams. From raw material procurement, to production, testing, sales and after-sales service, all steps have been controlled by a strict quality management system. Our factory has passed ISO, IS, BISI certification, SGS, Intertek audit. With the advantages in price, quality and service, we have established long-term and stable cooperative relationships with many well-known brands. Topwell always attached the great importance to the long term cooperation with customers. No matter the order is big or small, we do our best to support you the highest quality with favorable price. We believe that Topwell Power can be your best battery supplier!

Contact us to discuss your requirements of 3.2v Lithium Battery. Our experienced sales team can help you identify the options that best suit your needs.