The relationship between lithium ion battery and 18650 battery pack

Lithium is the lightest of all metals used in batteries, has the highest electrochemical potential, and provides the highest energy density by weight. Rechargeable batteries that use lithium metal anodes (negative electrodes) are capable of providing both high voltage and excellent capacity, resulting in extraordinary high energy density.

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After much research on rechargeable lithium batteries during the 1980s, it was found that the charge/discharge cycle causes changes in the lithium electrode. These transformations reduce thermal stability, causing potential thermal leakage conditions.

When this occurs, the temperature of the cell rapidly approaches the melting point of lithium, resulting in a violent reaction called “flame opening”. A large number of rechargeable lithium batteries shipped to Japan had to return in 1991 after a battery in a cell phone released flammable gases and caused damage to one’s face. Because of the inherent instability of lithium metal, especially during charging, research has led to a non-metallic lithium battery that uses lithium ions.

Although slightly lower in energy density than lithium metal, lithium-ion is safe, certain precautions are taken when charging and discharging.

Over 2 or maybe 3 years, the battery often fails. It should be mentioned that other chemicals also have age-related degenerative effects. This is especially true for NiMH batteries if exposed to high ambient temperatures. Storing the battery in a cool place slows down the aging process of the Lithium-Ion (and other chemical) batteries. Suppliers recommend storing at 15 ° C (59 ° F). In addition, the battery should only be partially charged when stored. Extended storage is not recommended for Lithium-Ion batteries.

Buyers should be aware of date of manufacture when purchasing replacement Lithium-Ion batteries. Unfortunately, this information is often encoded in an encrypted serial number and is only available to the manufacturer. The most cost-effective lithium-based battery is a battery pack that uses the 18650 cylindrical cell aka 18650 Battery Pack.

This battery is rather bulky but suitable for portable applications such as mobile computing. If a thinner battery pack is required (thinner than 18 mm), the Lithium-Ion Prismatic Cell is the best choice. There is little or no gain in energy density by weight and size over the 18650, however the cost is more than double. If ultra-thin geometry is required (less than 4 mm), the best choice is Lithium-Ion Polymer. This is the most expensive option in terms of energy cost. The Lithium-Ion Polymer offers no appreciable energy savings over conventional Lithium-Ion systems, nor does it combine the durability of the 18650 cell.

What are the best brands of 18650 batteries?

In addition to looking at the specifications it is advisable to choose brands with a minimum of quality and escape the cheapest Chinese marches, of doubtful reliability and that exaggerate capacities and can even be dangerous. Although it is not usual, we must not forget that there is a certain risk of explosions and it is not worth saving a few dollars to buy a bad custom lithium ion battery.

Where to buy?

Although there are many manufacturers and models, in many physical stores the offer is quite small, especially in terms of manufacturers and high intensity batteries. In Amazon you can find countless brands among its wide catalog at adjusted prices. In addition to the variety available is a trusted online store with good opinions and fast shipments.

The counterfeit of this type of batteries is quite common, so we recommend you follow some tips so that you do not get scammed:

  • Purchase from warranty sellers, it is not advisable eBay, AliExpress or similar
  • Beware of too cheap products
  • Do not buy capacities greater than 3450 mAh
  • Do not buy ultrafire outside the official distributor, it is one of the most counterfeit.

Hopefully this information is useful for you!