What is the difference between AA battery and 18650 battery?

What is the difference between AA battery and 18650 battery?


As the power source of modern electronic devices, batteries play an important role in our daily lives and work. Among them, AA batteries and 18650 batteries are two very common and representative battery types. They differ significantly in many aspects. So let’s dive into the differences between these two battery types to help you better understand and choose the one that best suits your actual needs.

What is AA battery?

AA batteries are also commonly called NO. 5 Battery. Generally speaking, the nominal voltage of AA battery is 1.5V. Its capacity ranges from 1800mAh to 2700mAh. In terms of size, the size of the AA battery is about 14×50mm, which is smaller than the 18650 battery.

By simple classification, AA batteries are divided into rechargeable batteries and non-rechargeable batteries. For example, AA batteries made of lithium-ion, nickel-metal hydride, and nickel-cadmium batteries are rechargeable batteries. And the typical AA batteries that people talk about are usually non-rechargeable.

What is 18650 battery?

The 18650 battery is mainly composed of lithium-ion batteries, and its physical size is approximately 18×65mm. The nominal voltage of the 18650 battery is 3.2V to 3.7V. Its nominal capacity is between 1800mAh and 3500mAh. 18650 batteries with different chemical compositions may have slightly different voltages and capacities.

In addition, the physical shape of the anode of the 18650 battery sometimes varies. That is, some of its batteries have tip-shaped anodes, while others have flat ones.


What is the difference between AA battery and 18650 battery?

Size Difference

There is an easily identifiable size difference between AA batteries and 18650 batteries. Although they are both cylindrical in shape, the 18650 battery is physically larger than the AA battery. The diameter of the 18650 lithium battery is 18mm and the height is 65mm. Generally speaking, the diameter of AA battery is 14mm and the height is 50mm. The height and diameter of the 18650 battery are larger than that of the AA battery. This size difference makes the two batteries unable to be mistakenly interchanged in applications.

Weight difference

In terms of weight, AA batteries are smaller and lighter, while 18650 batteries are larger and heavier. This weight difference gives them different characteristics when using and carrying them. However, it should be noted that the weight difference between the two batteries may vary due to the different materials used in the battery manufacturing.

Chemical differences

The 18650 battery is a rechargeable lithium-ion battery of a specific size. Its working principle is based on the migration and reaction of lithium ions between the positive and negative electrodes. 18650 batteries are usually made of lithium iron phosphate or NiCoMn ternary materials. This type of battery is widely used in various electronic products such as laptops, electric vehicles, etc. due to its size and characteristics.

AA batteries may come in various types such as alkaline, nickel-cadmium, nickel-metal hydride, zinc-carbon, or lithium-ion batteries. Its working principle and chemical reaction mechanism are somewhat different from those of the 18650 battery.

Voltage difference

The voltages of 18650 batteries and AA batteries are at different levels. Generally speaking, AA batteries (NO. 5 Battery) have a standard rated voltage of 1.5V. The 18650 battery has a different voltage than the AA battery, and its nominal voltage is 3.7V. 3.7V is the most typical voltage value of 18650 lithium-ion battery. The voltage differences between these two types of batteries directly affect their practical applications.

Capacity difference

The 18650 battery has a larger volume and has a larger capacity compared to AA batteries. At least for now, the capacity of 18650 batteries is 1800mAh~3500mAh, while the capacity of AA lithium-ion batteries is 1700~2700mAh. The capacity of alkaline AA batteries is 600~2700mAh.

Energy density difference

The energy density of 18650 battery is higher than that of AA battery, and it can be used for a longer time after being fully charged. Because it can hold more lithium ions and thus store more electrical energy. However, it should be noted that this comparison is based on the traditional AA battery using zinc-manganese oxide (Zn-MnO2) or zinc-silver oxide (Zn-AgO) as the cathode material, while the 18650 battery uses lithium-cobalt oxide Li-ion technologies such as Li-CoO2 or Li-Nickel Manganese Cobalt Oxide (Li-NMC). Therefore, if the AA battery is also made with lithium-ion technology, the situation may be different.

Difference in charge and discharge cycle times

There are two types of AA batteries: rechargeable and non-rechargeable. In the case of an AA alkaline battery, which produces electricity through a single chemical reaction, it is usually disposable and non-rechargeable. If it is a NiMH or NiCd rechargeable AA battery, it can be recharged.

Relatively speaking, the 18650 lithium-ion battery works on the principle that lithium ions move from the anode to the cathode during charging and discharging. This movement is reversible, meaning the battery can be charged and discharged repeatedly. Compared to non-rechargeable AA alkaline batteries, 18650 batteries can be cycled for 300 to 500 complete charge cycles. That said, 18650 batteries generally have longer battery life.

Application differences

Due to the differences in size, voltage, capacity, energy density, etc. between AA batteries and 18650 batteries, their application fields will also be different. First, AA batteries are favored for their smaller size and wide range of uses. It is often used in some household items or applications that require lower voltage power. Such as toys, clocks and remote controls, etc. In contrast, the 18650 battery can be used in more power-hungry, higher-power applications due to its higher energy density and voltage. Such as power tools, flashlights, laptop batteries, electric vehicles, etc.

What is the average lifespan of a AA battery?

With normal use, a typical AA battery will last 2 to 3 years. If it is a lithium-ion AA battery, it can be recycled for more than 3 years if it is properly maintained and charged and discharged in a timely manner. However, the average life of AA batteries may be affected by a variety of factors, including battery type, frequency of use, ambient temperature, charging method, etc. Therefore, we cannot give a too accurate average life value.

If you want to extend the life of your AA batteries, it is recommended to charge them using an appropriate charger as recommended by the manufacturer. At the same time, it's best to avoid storing batteries in environments with high temperatures or humidity, and to minimize the chance of leaving batteries dormant for long periods of time.

What types of AA batteries are there? Which AA batteries are the strongest?

AA batteries are divided into four main types according to their chemical properties: lithium-based (rechargeable), zinc-carbon, alkaline, and nickel-based (NiMH, NiZn). Comparing different types of AA batteries, lithium-ion AA batteries may have more advantages. Its battery capacity, charging protection performance, self-discharge rate, etc. perform better than other types of AA batteries.

How many times can an 18650 battery be charged?

Your 18650 battery can be charged up to 4000 times. If it is an 18650 battery that is frequently used in high consumption applications, its cycle life may be shortened. So, how to extend the cycle life of 18650 batteries? This may require you to control the number of battery cycles as much as possible and develop good battery charging and discharging habits.

Can AA batteries (NO. 5 Battery) be replaced by 18650 batteries?

Generally speaking, AA batteries and 18650 batteries are not directly interchangeable. We do not recommend that you replace AA batteries with 18650 batteries.

There are big differences in the voltage and size of these two batteries. Therefore, if you want to replace the original AA battery with an 18650 battery in a specific device, or replace the 18650 battery with an AA battery, it is difficult and challenging to establish. It is difficult to ensure that the voltage and size of these two different battery types match the requirements of the device.

However, some 18650 batteries are interchangeable with 21700 batteries, which are rechargeable lithium-ion AA batteries with the same voltage.

AA battery VS 18650 battery? Which battery is better?

From the perspective of battery application potential, 18650 batteries are better than AA batteries. For example, Tesla uses 18650 batteries as its power source in Model Y, and most electric motorcycles and scooters also choose to use 18650 batteries. In short, 18650 batteries can be widely used in various fields. This further proves its advantages in energy density, charging efficiency, environmental protection and material quality. And there is no doubt that 18650 batteries have huge application potential.

However, in terms of commercial popularity, AA batteries perform better than 18650 batteries. AA batteries are a common battery type that have been around and widely used for decades. In comparison, 18650 batteries may have been popular for less than ten years.

In short, AA batteries and 18650 batteries each have their own advantages. If you have to choose a better one between these two batteries, the 18650 battery may be better than the AA battery. But we also said that there are differences between these two different types of batteries. When you want to replace your electronic device with a new battery, your first consideration should be the purpose and compatibility of the battery. You need to choose the right battery for your device and then choose the one with better quality.

Where can I find or buy 18650 batteries or rechargeable AA lithium batteries?

You can find your local electronics retailer or battery store, which usually sells various models of batteries, including 18650 batteries and rechargeable AA lithium batteries. In addition, you can also find reliable online battery retailers on various shopping websites who can provide you with purchasing services.

Of course, there is a more convenient and faster purchasing channel - batterymall.com. Our website sells various types of battery products, including different models of 18650 batteries and rechargeable AA lithium ion. We will provide a 2-year warranty for the battery you purchase, so you don't have to worry about quality issues.


All in all, there are significant differences between 18650 batteries and AA batteries in terms of energy density, voltage, service life, and applicable scenarios. Therefore, when we choose a battery, it is best to make a reasonable choice based on the operating needs and scenarios of the specific device to achieve the best performance.

Finally, if you want to know more about batteries, please visit: BatteryMall.com/support.

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