Large Power is a provider of customized solutions and products for special lithium power systems. It can provide a complete set of power supply solutions from a single cell, battery management system,charger to battery pack according to customer requirements.

  • Cell selecting
  • Structure design
  • Battery management system design
  • Voltmeter design
  • Charger design

A custom 18650 lithium battery pack is widely used in different fields, including in medical devices, special equipment, , in the military, instruments, handheld devices, security and communications, etc.

What is An 18650 Lithium Battery?

18650 refers to the appearance specification of the battery, which is a standard battery model determined by SONY in order to save costs. 18 means 18mm in diameter, 65 means 65mm in length, and 0 means cylindrical battery.

The nominal voltage of a 18650 lithium battery is usually 3.6V or 3.7V, the minimum discharge final voltage is 2.75V, and the normal capacity is 1200 ~ 3500mAh.

The 18650 battery is the most commonly used battery type in life and industry. No matter which manufacturer produces the 18650 lithium battery, the overall size is certain. The difference is that the maximum capacity and the highest energy density ratio.

Top 18650 Lithium Battery Cell Model Meter

Brand

Model

Nominal Voltage(V)

Nominal Capacity(mAh

Continuous Discharge Rating(A)

Chemistry

Style

Protected

Approximate Weight(g

Approximate Dimensions

(mm)

LG

INR18650HG2

3.6

3000

20

INR

Flat Top

No

47.0

18.4x64.5

LG

LG18650HB6

3.6

1500

30

NMC

Flat Top

No

48.0

18.3x65.0

LG

ICR18650HE4

3.6

2500

20

ICR

Flat Top

No

47.0

18.5x65.2

SONY

US18650VTC3

3.6

1600

30

NMC

Flat Top

No

45.1

18.4x65.1

SONY

US18650VT4

3.6

2100

22

NMC

Flat Top

No

45.1

17.8x64.8

SONY

US18650VTC5

3.6

2600

20

NMC

Flat Top

No

44.1

18.2x65.0

SONY

US18650VTC5A

3.6

2600

25

NMC

Flat Top

No

47.8

18.2x65.0

SONY

US18650VTC5D

3.6

2800

25

NMC

Flat Top

No

46.4

17.9x64.7

SONY

US18650VTC6

3.6

3000

15

NMC

Button Top

Yes

47.1

18.5x69.5

Samsung

INR18650-20S

3.6

2000

30

INR

Flat Top

No

45.7

18.2x 64.8

Samsung

INR18650-25R

3.6

2500

20

INR

Flat Top

No

43.8

18.3x64.9

Samsung

INR18650-30Q

3.6

3000

15

INR

Flat Top

No

48.0

18.3x64.9

Panasonic

NCR18650B

3.6

3400

4.9

NCR

Flat Top

No

47.5

18.6x65.1

Panasonic

UR18650RX

3.6

1950

20

NCR

Flat Top

No

46.2

18.5x65.3

BAK

N18650CP-33

3.6

3200

0.67

INR

Flat Top

No

48.5

18.5x65.1

BAK

H18650CH

3.6

2600

0.52

INR

Flat Top

No

48.0

18.5x65.1

LISHEN

LR1865SK

3.6

2600

0.52

INR

Flat Top

No

47.0

18.5x65.2

LISHEN

LR18650LA

3.6

2000

0.4

INR

Flat Top

No

47.0

18.5x65.2

LARGE

LA18650-22

3.7

2200

0.44

INR

Flat Top

No

45.7

18.5x65.2

LARGE

LA18650-25

3.7

2500

0.5

INR

Flat Top

No

45.7

18.5x65.2

  • Japan: SANYO/Panasonic, SONY, etc.
  • South Korea: LG, Samsung, etc.
  • China: BAK, LISHEN, LARGE POWER, etc.
Panasonic

Panasonic
Established: 1918 Headquarters: Osaka, Japan
The Panasonic power battery business belongs to the energy field of the AIS sector, including secondary battery and energy equipment. Secondary battery equipment includes the Panasonic secondary battery business division and Tesla business division, which will greatly affect Panasonic performance growth.

SONY

SONY
Established: 1946 Headquarters: Japan
Established in May 1946, this is one of the world's largest manufacturers of electronic products and a pioneer of the lithium battery industry. In July 2016, Murata acquired SONY's battery division. Now SONY is gearing up to push into electric car batteries.

LG Chem

LG Chem
Established: 1947 Headquarters: South Korea
This is a subsidiary of LG group, which is a leading chemical enterprise in South Korea mainly engaged in the production of petroleum chemistry, batteries, advanced materials and life science products. It dominates the global market in the fields of automobile battery, ESS battery and mobile device battery.

Samsung SDI

Samsung SDI
Established: 2011 Headquarters: South Korea
This is a subsidiary of South Korea's Samsung group, which is mainly engaged in the display and lithium battery production. Samsung SDI R&D center is located in South Korea, Japan, Russia and other countries, and has offices in Taiwan, Germany, Malaysia, India, Vietnam, etc. It is one of the top 100 lithium battery manufacturers in the world.

LISHEN

LISHEN
Established: 1997 Headquarters: Tianjin, China
Tianjin Lishen Battery Co., Ltd., a representative brand of lithium battery in China, it is one of the professional manufacturers of lithium battery with large investment and the highest technical level in China.

BAK

BAK
Established: 2001 Headquarters: Shenzhen, China
Shenzhen BAK Technology Co., Ltd., a well-known brand of lithium battery, a battery supplier of HP, Dell, Lenovo, etc. It is a world-renowned manufacturer of lithium battery, integrating research, development, production and sales.

LARGE POWER

LARGE
Established: 2001 Headquarter: Dongguan, China
Dongguan Large Electronics Co., Ltd is a provider of customized solutions and products for special lithium power systems. It is mainly engaged in the research, development, production and sale of special lithium batteries, low-temperature batteries, explosion-proof batteries, military lithium batteries and medical lithium batteries.

An 18650 lithium battery charger is specially used to charge an 18650 battery. Lithium battery has high demand on charger. It needs a protection circuit, so the lithium battery charger usually has higher more precise of control. It can charge athe lithium battery with a constant current and constant voltage.

  • The working state of lithium battery charger is consistent with the battery. If the charger works in the state of lithium battery and charges a NI-MH battery or nickel-cadmium battery, the battery will be charged insufficiently and the working time will be greatly reduced. If the charger works in the state of nickel battery to charge lithium battery, the lithium battery will be overcharged. It will seriously affect the battery cycle life.
  • Make sure the battery is fully charged,when the lithium battery charger is fully chargedd. You can remove it. The lithium battery can be removed from some chargers when the fully charge indicator light is on, while with some chargers you cannot remove the battery until all the indicator lights are on.
18650 Lithium Battery Charger

According to Anode Chemical Materials
Lithium cobalt 18650, lithium manganate 18650, ternary 18650, lithium iron phosphate 18650, Ni-Mh 18650 (uncommon)

According to Discharge Performance
Capacity battery and power battery

Capacity 18650 Battery Cell
A capacity battery is a battery that pursues maximum capacity as far as possible in a small volume. The capacity of this kind of battery is relatively large, and tends to be more than 3000mah, while the discharge current is relatively small. It is suitable for a power bank, a flashlight, security, a mine lamp, an alarm, medical equipment, etc. They consume power at a sustained rate for a long period of time without requiring high current.

Power 18650 Battery Cell
A power battery does not have a high capacity. It is 2000-2400mah, but the discharge rate is large. It can reach more than 3C discharge, or even more than 10C. It is suitable for equipment that needs high current, such as power tools, vacuum cleaners, vaping, model airplane, swing cars, unicycles, etc.

18650 Lithium Battery Cell
Common Battery Chemical Materials
Common 18650 Cell Prefixes
  • LCO - Lithium Cobalt Oxide(LiCoO2)
  • LMO - Lithium Manganese Oxide (LiMn2O4)
  • NMC - Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)
  • NCA - Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2)
  • LFP - Lithium Iron Phosphate(LiFePO4)

There are two kinds of heat shrinkable tubes for an 18650 lithium battery: PVC and PE. Most manufacturers will choose PVC heat shrinkable tubes because of their low cost and easy shrinkage.

  • PVC heat shrinkable tubes are cheap, but are easy to break, so their operational period is not long, and they are difficult to repair if they are broken.
  • A PE heat shrinkable tube is not easy not easy to be cut. It has high temperature resistance, and won’t scald because a battery has overheated.

How to Choose 18650 Lithium Battery

An 18650 battery generally has the advantages of large capacity, long life, high safety performance and a wide range of use. When purchasing an 18650 battery, you should generally learn about its brand, capacity, current, voltage and operating temperature, before you can select a good 18650 battery.

According to the requirements of electrical appliances, size and characteristics of electrical consumption, choose the appropriate battery type and size to buy.

At present, there are Panasonic/Sanyo, SONY, Samsung, LG and other world famous brands. Panasonic, Sanyo are capacity battery manufacturers. LG, SONY, and SAMSUNG manufacture 18650 power battery better.

The nominal capacity of an 18650 battery will affect the battery life. The unit is "mAh". The higher the capacity, the better the battery life is.
For example, a 2800mAh battery can last for 2 hours at 1.4A.
At present, the capacity of 18650 battery is seriously unveracious, so we try our best to choose a famous brand battery cell through proper channels.

Charge-discharge rate = charge-discharge current (A)/rated capacity (Ah)
Charge and discharge rate refers to the current value required for the battery to release its rated capacity within a specified time. It is numerically equal to the multiple of the rated capacity of the battery. The unit of battery discharge rate is generally C (short for c-rate), such as 0.5C, 1C, 5C, etc.

Internal impedance refers to battery self-consumption. The smaller the internal impedance, the better the discharge capacity is. Internal resistance will be written to general battery introduction page. Try not to buy batteries with internal impedance more than 100 mΩ.

Temperature is a major factor which affects 18650 lithium battery life. The higher the temperature, the faster the aging rate of the lithium battery will be, and the higher the temperature, the greater the damage suffered by the lithium battery will be.

The so-called button top and flat top are designed by various manufacturers according to their own assembly needs, battery safety, battery capacity and other factors, and there is no essential difference.

Button Top and Flat Top 18650 Button Top and Flat Top 18650

The 18650 lithium battery with PCM is 4-6mm higher than the 18650 lithium battery without PCM. It is also slightly more expensive, but it is safer.
The 18650 lithium battery with PCM can prevent over-discharge of the battery (over-discharge will cause a lithium battery overheat, burn or, in extreme cases, explode).

Glare flashlights and headlamps generally do not have protective circuits. It is recommended to purchase a protected 18650 lithium battery.

How Do You Avoid Buying A Fake 18650 Lithium Battery?

A 18650 battery is a common battery model. Some bad battery factories replace 18650 battery with counterfeit batteries, the following will tell you how to identify the fake 18650 lithium battery.

The 18650 battery has a beautiful appearance. The battery package is smooth and wrinkle-free, and all have a strict battery tracking mark. Detailed battery data can be seen in the code spraying mark on the battery membrane.

Weigh the batteries on an electronic scale, and then compare the weights. The weight of 18650 battery is generally 45-48g, while the weight of the fake 18650 battery is generally 10g. There are also fake 18650 batteries mixed with mud, and the weight of the mud 18650 battery is generally 30g.

The voltage of a the genuine 18650 battery is about 3.7V, while a fake 18650 battery doesn’t have a voltage, that is, the voltage of the fake battery is zero (0V).

A counterfeit 18650 battery has no internal impedance or its resistance value is very small, while a genuine 18650 battery has internal impedance is usually around 20 mΩ.

Battery Internal Impedance Tester

Basic Structure of 18650 Lithium Battery Pack

The basic structure of lithium-ion battery is composed of four parts: the cell, the PCM, the cases and the lead/terminal.

The battery cell is the most important component of the battery. It is the carrier of energy conversion.
It is mainly divided into the cylindrical lithium-ion cell, the prismatic lithium-ion cell, the pouch cell and so on.

The PCM is an electronic module used to protect the normal operation and prevent the unusual abnormal accidents.
According to the quantity, it can be divided into single board and multi board.
According to the product category, it can be divided into an ordinary board, an intelligent board and a power board.
The main parameters include overcharge, over-discharge, overcurrent, self-consumption, internal resistance, leakage protection and so on.

This includes various specifications and brands from line #32 to line #10.
It includes all kinds of terminal heads.

The case is used to fix and seal the cell and PCM together, so as to complete the matching function with the main engine.
Common materials of the case: ABS, ABS+PC, PC, etc.
The main indicators of the case are: color, material, matching, mechanical strength etc.

Structure of 18650 Lithium Battery

18650 Lithium Battery Connection

In the actual use of batteries, high voltage and large current are often required, which need to connect several single batteries in series or parallel (or both), we call it battery pack. The 18650 lithium battery pack needs a certain standard.

18650 battery in series: When multiple 18650 lithium batteries are connected in series, the battery pack voltage is the total of all battery voltage, but the capacity remains unchanged.

Schematic Diagram of 18650-4S Connection
Schematic Diagram of 18650-4S Connection

18650 battery in parallel: If you connect multiple 18650 lithium batteries in parallel, you can get more power. The parallel connection of lithium battery keeps the voltage constant, while the capacity increases. The total capacity is the sum of the total capacity of all single lithium batteries.

Schematic Diagram of 18650-4P Connection
Schematic Diagram of 18650-4P Connection

Series and parallel connection of 18650 battery: the method of series and the parallel connection is to connect several lithium batteries in series and then connect the battery packs in parallel. It not only improves the output voltage, but also the capacity.

18650-2S2P Connection Diagram
18650-2S2P Connection Diagram
  • Series and parallel connection of lithium batteries need battery cell matching.
    Lithium battery matching standards: voltage≤10mV resistance ≤5mΩ capacity≤20 mA
  • Battery with the same voltage
  • Different batteries have different voltages. After being connected in parallel, the high-voltage battery charges the low-voltage battery, which consumes the power and may lead to accidents.
  • Battery with the same capacity
  • Connect batteries with different capacities in series. For examples, same battery may be different from the aging degree. Batteries with small capacity will fully discharge first, then the internal resistance will increase. You also need to use the same battery if connect in series. Otherwise, after connecting batteries with different capacities in series (for example, same battery may be different in the aging degree), the batteries with small capacity will fully discharge first, then the internal resistance will increase.
  • At this moment, the batteries with large capacity will discharge through the internal resistance of the batteries with small capacity, and then reverse charge. In this way, the voltage on the load will be greatly reduced, the battery will be unable to work, and the large capacity battery is only equivalent to the small capacity battery. Long-term use may cause accidents.
  • The battery pack requires a high degree of consistency (capacity, internal impedance, voltage, discharge curve, cycle life).
  • The cycle life of the battery pack is lower than that of a single battery.
  • Different batteries have different voltages. After being connected in parallel, the high-voltage battery charges the low-voltage battery, which consumes the power and may lead to accidents.
  • It needs to be used under limited conditions (including charging, discharging current, charging mode, temperature, etc.)
  • After the lithium battery pack is formed, the battery voltage and capacity will be greatly increased, so it must be protected. It also needs charging balance, temperature, voltage and overcurrent monitoring.
  • The battery pack needs to meet the design requirements of voltage and capacity.

Customized 18650 Lithium Battery Packs that We Make

  • 18650 3.6V 2600mAh Low Temperature battery Samsung Battery for Flashlight
    3.6V 2600mAh
    Flashlight
    18650 Low Temperature battery
  • 11.1V 10Ah 18650 Lithium Ion Battery Sanyo Battery for Portable B-mode Ultrasound Machine
    11.1V 10Ah
    Portable Ultrasound Machine
    18650-3S4P Lithium ion Battery packs
  • 18650 46.8V 13Ah Energy Storage Battery Panasonic Battery for Rail Drilling Machine
    48V 13Ah
    Rail Drilling Machine
    18650-13S4P Lithium Battery Packs
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