18650 Batteries: An Overview

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18650 battery

Stanley Whittingham, John Goodenough and Akira Yoshina are the men whose works led to the emergence of the lithium ion battery. Whittingham, an English chemist and Exxon staff, was working during the oil crisis of the 1970s. He wanted a rechargeable battery that could help end the dependence on fossil fuels one day. He first experimented with titanium disulfide and lithium metal as the electrodes. But his effort was bedeviled with serious obstacles.

One such challenge was an accidental short-circuiting and subsequent inflammation of his batteries which led to the halting of the experiment by Exxon. In the 1980s, instead of the titanium disulfide used by Whittingham, Goodenough experimented with lithium cobalt oxide as the cathode. His efforts were an improvement on Whittingham’s work because his new battery had a much higher energy potential. 

A few years after Goodenough’s breakthrough, Akira Yoshino used reactive lithium metal as anode to invent the first prototype lithium ion battery. His battery was the most stable in terms of performance. Many years later, in 2019, the three men were honored with the Nobel Prize in Physics for the work in the development of the lithium ion battery.

What is a Lithium ion Battery?

A Lithium ion battery can be defined as a battery technology whose electrochemistry uses lithium ions as its main component. As noted above, Li-ion batteries can be made with a variety of electrodes. Graphite the main anode used in lithium ion batteries. 

Cathodes usually vary according to the devices the battery will power.  For example, a cathode containing liquid cobalt oxide is widely used in the li-ion batteries of electronic devices like mobile phones and laptops. Other products such as electric cars use liquid manganese oxide as cathode. Liquid iron phosphate is yet another material used a cathode in Li-ion batteries. Ether is the commonly used electrolyte. There are a number of li-ion chemistries such as:

  • Lithium cobalt oxide
  • Lithium manganese oxide
  • Lithium iron phosphate
  • Lithium nickel manganese cobalt oxide
  • Lithium nickel cobalt aluminum oxide
  • Lithium titanate

What is an 18650 Battery?

18650 battery

The 18650 battery is a type of li-ion rechargeable battery that derives its name from its 18mm × 65mm (diameter × height) dimensions and its cylindrical nature. In other words, while the first 4 digits represent its dimensions, the last digit indicates that it is a cylinder cell. I8650 batteries are used in a wide spectrum of devices including flashlights, laptops, digital cameras, remote controllers and others.

They are also very ideal for high-drain devices because of their superior capacity and discharge rates. 18650 batteries are usually larger than AA batteries in both height and diameter and cannot be used in place of either AA or AAA size cells.

Sometimes, 18650 batteries are modified to include a button top and/or internal protection circuit (more on this later). Such a modification can extend the height of the battery to 70mm and beyond. Therefore, it is necessary to read the manufacturers product manual in order to determine the actual dimensions or specifications you need for your device before investing in an 18650 battery.  

How 18650 Batteries Work

During a discharge, cycle, lithium atoms present in the anode are ionized and isolated from their electrons. These lithium ions then travel from the anode to the cathode, passing through the electrolyte in the process. On getting to the cathode, they merge with the electrons they were earlier isolated from and then electrically neutralize.

The small size of the lithium ions makes it easy for them to travel through the micro-permeable separator between anode and cathode. Also, the miniature size of lithium enables li-ion batteries to have a very high voltage and charge storage per unit mass and unit volume.

18650 battery

Classifications of 18650 Batteries

Protected vs. Unprotected Batteries

Protected batteries are those that include a small electronic circuit usually located at one extreme of the battery. The circuit provides protection against things like extreme temperatures, short circuiting, overcharging, over-discharging and any damages that may arise from leaking and explosion.  

Unprotected batteries are not designed with any protective circuit. Hence, they are more affordable albeit they have a greater likelihood of causing any of the problems that circuits are meant to guard against.

Flat Top vs. Button Top Batteries

18650 batteries usually come in two variations - flat top and button top. This classification is mainly concerned with the battery contacts, particularly the positive contact. Button top batteries will protrude a bit unlike flat top batteries that align perfectly.


Where to buy High Quality 18650 Batteries

These are very difficult times characterized by economic downturns and higher unemployment all over the world due to the global pandemic. In such times, it is ideal to purchase long lasting and highly efficient 18650 batteries in other to avoid overspending on one item. At a company like EBL 18650 Battery, you’ll find all the solutions you seek when it comes to 18650 batteries. EBL is a business that has been stocking various high grade batteries of all sizes for many years.  

ebl 18650 battery

One of the battery types available at EBL is the BRC 18650 Li-ion 3.7V 3000 mAh rechargeable batteries (shown above) for portable devices like flashlights, digital cameras, remote controls, wall clocks, etc. This 1.83 oz battery with a height of 66±0.6 mm and a diameter of 18.3±0.4 mm will offer you everything you are looking for in an 18650 li-ion battery. In a nutshell, the BRC 18650 3.7V 3000 mAh rechargeable batteries have been produced with premium raw materials that will offer you the following:

  • Ultra long life
  • High performance/quality
  • Compatibility with several devices
  • Eco-friendliness (does not contain Hg/Cd/Pb)

The EBL 18650 rechargeable battery comes in 2/4/6/16 packs

For all your 18650 (and other battery) needs, visit EBL today! EBL is one company with the professional and technological expertise to help power many of your devices.   


“3.7V” implies peak or optimal 18650 battery output in terms voltage. It will decline with battery use.

“3000 mAh” is an indication of amp hours of current that can be generated by an 18650 li-on rechargeable battery. The higher the number, the more the amp hours that can be generated.

A 3.7V 18650 battery charging circuit should have a 5V power output if the battery is protected and a 4.2V output if not protected.

What devices are powered by flat top 18650 battery?

A flat top 18650 battery is a type of rechargeable lithium-ion battery that is commonly used in a variety of electronic devices, such as laptops, power banks, and electronic cigarettes. The 18650 battery gets its name from its dimensions: it is 18mm in diameter and 65mm in length. The "flat top" refers to the fact that the battery does not have a protruding positive terminal, or "button top," like some other types of batteries. Flat top 18650 batteries are used in a wide range of applications due to their high energy density, long lifespan, and ability to be recharged.

New product: Flat Top 18650 Battery

flat top 18650 battery

1 comment

  • karl v hawley

    I’m looking for batteries not made in China the Chinese ones always lie about their milliamps half hours.

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