What is an 18650 Battery?
The 18650 battery is a lithium-ion rechargeable battery originally developed by Sony Corporation in Japan. The name "18650" refers to the battery's dimensions: 18mm in diameter and 65mm in length, with the "0" indicating that it is a cylindrical cell. Due to its excellent performance and versatility, the 18650 battery has become one of the most widely used types in the battery industry today.
Main Features
High Energy Density: 18650 batteries offer a high energy density, allowing them to store a large amount of energy in a relatively small size.
Long Lifespan: With proper usage and maintenance, 18650 batteries have an extended cycle life, supporting numerous charge and discharge cycles.
Safety: With advancements in technology, the safety features of 18650 batteries have greatly improved. These include overcharge protection,
over-discharge protection, and short-circuit protection.
Wide Applications: Thanks to their superior performance, 18650 batteries are commonly used in a variety of electronic devices, such as flashlights, laptops, and electric vehicles
Voltage: The nominal voltage of an 18650 lithium-ion battery is typically 3.7V, and it can reach up to 4.2V when fully charged.
Capacity: The capacity of a standard 18650 lithium battery ranges from approximately 1500mAh to 3500mAh, depending on the brand and model.
Charging Time: 18650 lithium batteries generally require 2 to 3 hours to fully charge, depending on the charger’s power output and the battery’s capacity.
Item | Condition / Note | Specification |
---|
2.1 Energy | Std.charge / discharge | Nominal 3500 mAh Minimum 3400 mAh |
2.2 Nominal Voltage | Average | 3.635V |
2.3 Standard Charge | Constant current | 0.5C (1700mA) (Refer to 4.1.1) |
| Constant voltage | 4.2V |
| End current(Cut off) | 50mA |
2.4 Max.Charge Voltage |
| 4.2±0.05V |
2.5 Max.Charge Current |
| 1.0C(3400mA) |
2.6 Standard Discharge | Constant current | 0.2C (680mA) (Refer to 4.1.2) |
| End voltage(Cut off) | 2.5V |
2.7 Max.Discharge Current |
| 10A |
2.8 Weight | Approx. | Max.49.0 g |
2.9 Operating Temperature | Charge | 0~45℃ |
| Discharge | -20~60℃ |
2.10 Storage Temperature | 1 month | -20~60℃ (for shipping state) |
| 3 month | -20~45℃ |
| 1 year | -20~20℃ |
Installing the battery into the pack
-. The cell should be inspected visually before battery assembly into the pack.
-. Damaged cell should not be used. (Damaged surface, can-distortion, electrolyte-smell)
-. Different Lot Number cells should not be packaged into the same pack.
-. Different types of cells, or same types but different cell maker’s should not be used together.
Design of battery pack
-. The battery pack should not be connected easily to any charger other than the dedicated charger.
-. The battery pack has function not to cause external short cut easily.
Charge
-. Charging method is Constant Current-Constant Voltage (CC/CV).
-. Charging should be operating under maximum charge voltage and current which is specified in the product
specification. (Article. 2.4, 2.5)
-. The battery should be charged under operating temperature specified in the product specification. (Article. 2.9)
Discharge
-. Discharging method is Constant Current (CC).
(In case of using the battery for mobile equipment, discharging mode could be Constant Power.)
-. Discharging should be operating under maximum discharge current which is specified in the product
specification.
-. Discharging should be done by cut off voltage which is specified in the product specification.
-. The battery should be discharged under operating temperature specified in the product specification.
Protection Circuit
-. The protection circuit should be installed in the battery pack, charger.
-. Charger or pack should have voltage sensing system to control over charge or discharge in order to
maintain the battery’s normal operating mode and protect cell imbalance.
-. Charger or pack should have warning system for over temperature, over voltage and over current