18650 Battery Supplier

18650 is the originator of lithium-ion batteries – a standard lithium-ion battery model set by Japan’s SONY company in order to save costs, where 18 indicates a diameter of 18mm, 65 indicates a length of 65mm, and 0 indicates a cylindrical battery.

The 18650 battery lifespan theory is 500 cycles of charging. Due to the large capacity per unit density, most of them are used in notebook computer batteries. In addition, because 18650 has very good stability at work, it is widely used in major electronic fields: commonly used in high-end strong light flashlights, portable Power supplies, wireless data transmitters, electric thermal clothing, shoes, portable instruments, portable lighting equipment, portable printers, industrial instruments, medical instruments, etc.

18650 battery supplier

The advantage of 18650 batteries

  1. Big capacity. The capacity of 18650 lithium-ion battery is generally between 1200mah and 3500mah.
  2. Long lifespan. The cycle life of normal use can reach more than 500 times.
  3. High safety performance. Non-explosive, non-flammable; non-toxic, non-polluting.
  4. Can be combined in series or parallel to form 18650 lithium-ion battery packs.
  5. Wide range of use. Suitable for energy storage power supply, power battery and consumer electronics.

How long does it take to charge a 18650 battery?

Standard charging method: charge with 0.2C5 constant current until the battery terminal voltage is 4.20V, change to constant voltage charging, and when the charging current is less than 0.01C5, it is regarded as fully charged.

The standard charging method is often used for the calibration of battery capacity. Because the charging is too slow, it is rarely used in daily use.

Fast charging method: charge with 1C5 constant current until the battery terminal voltage is 4.20V, change to constant current charging, until the charging current is less than 0.01C.

Notes on the fast charging method:

The initial charging current should not be too large to avoid overheating of the battery, leakage and bursting.

When the battery terminal voltage reaches 4.20V, it must be switched to constant voltage immediately. The voltage requirement is relatively high (error <0.5%), and it must be measured with a multimeter with more than four and a half digits.

18650 battery applicant

18650 battery packs are commonly used in a broad spectrum of applications, including:

  • Energy storage. Mainly used in base station power supply, clean energy storage, grid power storage, home solar storage system, etc.

  • Power class. Mainly refers to electric vehicles, electric bicycles, new energy vehicles, etc.

  • Digital consumer electronics. Mobile phones, tablets, laptops, electric toys, MP3/MP4, earphones, power banks, model airplanes, power banks, etc.

How to test 18650 battery?

  • Prepare the multimeter, touch the multimeter pen to the positive and negative poles of the 18650 battery, and conduct a simple voltage test. Generally, the voltage of the genuine 18650 iron-lithium battery is about 3.20V, the voltage of the A-product 18650 lithium battery is about 3.8V, and the bad 18650 battery has a voltage of about 3.8V. The fake battery is generally low voltage or no voltage. If it is a fake battery, its voltage output is 0V. A simple comparison based on the voltage test results can distinguish the quality of the battery.

  • Prepare the internal resistance tester, put the 18650 battery on the internal resistance test fixture to test the internal resistance. The counterfeit 18650 battery has no internal resistance or the internal resistance value is very small, while the internal resistance of the 18650 battery of product A is generally 30 Below milliohms, a simple comparison based on the test internal resistance results can also distinguish whether the battery is good or bad.


  • If you want to distinguish the quality of the battery more clearly, prepare the battery separation cabinet. After putting the battery on the cabinet, set the working steps and the battery parameters on the corresponding specification, and perform a capacity test. The capacity of product A after capacity separation All are up to standard.
Multimeter test
18650 battery test

How to discharge 18650 battery?

  • The discharge process of lithium batteries is balanced during operation. In theory, the discharge rate and depth of discharge should be paid attention to when discharging lithium batteries.

  • The depth of discharge is the ratio of the discharge capacity to the nominal capacity. The best reference indicator in practice is the voltage. How to discharge the lithium battery to make the depth of discharge more scientific? The general standard is: a lithium battery can be charged between 2.75V and 3V, because if it is lower than 2.75V, it is easy to cause “over-discharge” that is taboo for rechargeable batteries. When over-discharged, from the internal structure, One is that it will cause excessive volatilization of the electrolyte, and the other is that the negative electrode of the lithium battery reacts excessively to change the dielectric film, resulting in a decrease in the de-intercalation ability and a permanent loss of capacity.

  • Another parameter that can effectively explain how the lithium battery is discharged is the discharge rate. The discharge rate can also be converted into the discharge current. For example, if a 1800mAh battery is discharged at a rate of 0.1C, the discharge current is 180mAh, and the discharge current is usually smaller. . Therefore, in the discharge of lithium batteries, from the perspective of the depth of discharge, we should pay attention to supplementing nutrients; from the perspective of discharge current, we should pay attention to the long flow of water. Because the lithium battery does not have the memory effect of other secondary batteries, it is not necessary to care about how the lithium battery can be discharged to activate the battery.

    When the lithium battery is idle, there is actually a discharge phenomenon, which is called self-discharge.
18650 battery discharge

How to make a 12v 18650 battery pack?

  1. The number of cells

First of all, make a simple calculation according to the requirements of the battery pack for capacity and voltage, determine the capacity in parallel, and solve the voltage in series.

     2. Connection method

Since the lithium battery is strictly prohibited from overcharging and over-discharging, a protection board should be added. This determines that the battery pack must be connected in a parallel-to-serial mode. That is, connect 15 cells in parallel and then in series. This connection method has high requirements on the consistency of the cells, so it is necessary to do some classification and pairing work. That is, the internal resistance should be connected in parallel with the same or close resistance as possible.

     3. Protection board connection

Lithium battery protection boards are now sold online with many finished products. Connect the battery and the protection board as shown below.

18650 lithium-ion battery pack procedure as right flow chart

It includes the whole 14 steps to whole lithium battery packs. It includes cell inspection & test, solder PCB/nickel strip/cell, highland barley paper insulation, aging test, packing and delivery.

18650 lithium battery pack procedure

Manufactured to National Standard GB/T18287-2020

  • All are producing at 5S & dust free plant. Our daily production is up to 10K pieces.
automatic sorting machines
18650 battery sorting
our workers

Chemical Test

Automatic Welding

Final Testing

  • Cell Formation & Grading
  • Temp & Hum Controller
  • Short-circuit Test
  • Salt Spray Test
  • Molding System
  • Automatic Welding
  • Automatic Welding
  • Final Test
  • Packing

Need Any Custom 18650 Lithium Battery?

You will receive the charge & discharge curve

  • 12S2P Battery Pack, It is a 5A charge & 10A discharge curve test as a sample for your review.
Lithium battery test curve

Time - voltage & current

Lithium battery test performance

Capacity - voltage

Lithium battery test curve

Time - capacity & specific capacity

Lithium battery test curve

Cycle number-charge capacity & discharge capacity & charge specific capacity & discharge specific capacity

Product & Factory Certificates

  • All batteries are require related certification apart from lab testing, such as voltage, current measure, and each countries have different certificate demand.
  • Clients are welcome to have any 3rd party certification company verify our batteries or the factory documents.
  • We have been working with UL, TUV, SGS certication lab. All batteries approved by UL1642, UN38.3, IEC62133, PSE, KC, CB, MSDS certificate or report.
battery certificate

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FAQ of 18650 battery pack

  • Lithium-ion battery storage temperature

    The battery should be stored at room temperature, and charged to 40%~60% electric quantity.

  • What’s the lifespan of 18650 battery?


  • How long to get samples?
    Generally, 7 days lead time for small quantity samples.

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We will contact you within 1 working day, please pay attention to the email with the suffix “@hlcbattery.com”