26650 lithium batteries are a type of cylindrical lithium battery. They are used in power tools, lighting, wind and solar energy storage, electric vehicles, toys, instruments, UPS backup power supplies, communication equipment, medical equipment, and military applications. The model designation is: 26650, meaning a cylindrical battery with a diameter of 26mm and a length of 65mm. It is generally used to refer to lithium batteries, including primary lithium batteries and lithium-ion batteries. Common types include lithium batteries made with nickel-cobalt-manganese cathode materials and lithium iron phosphate materials—INR26650-3.6V-4500mAh and IFR26650-3.2V-3200mAh.
Relevant parameters of 26650 lithium battery
Cycling performance: 2000 cycles (1C charge/1C discharge, capacity retention ≥80%, 100% DOD) Maximum continuous discharge current: 9.6A
Pulse discharge current: 15A, 5s
Operating temperature: Charging: 0°C ~ 55°C; Discharging: -20°C ~ 60°C
Storage temperature: -20°C ~ 45°C
Battery weight: 86 g (approx.)
The nominal voltage of a single 26650 nickel-cobalt-manganese ternary lithium-ion battery is typically 3.6V.
Nominal capacity: 4500mAh (capacity range 4500-4650mAh)
AC internal resistance: ≤30mΩ (with PTC type)
Charging conditions: Cut-off voltage 4.2±0.05V, cut-off current 0.01C. (Note: Charge at a constant current of 0.5C to 4.2V, then charge at a constant voltage until the current drops to 0.01C to cut off.)
Discharge cutoff voltage: 2.75V
Cycling performance: 500 cycles (1C charge/1C discharge, capacity retention ≥70%, 100% DOD)
Maximum continuous discharge current: 13A
Pulse discharge current: 15A, 5s
Operating temperature: Charging: 0°C ~ 55°C; Discharging: -20°C ~ 60°C
Storage temperature: -20°C ~ 45°C
Battery weight: 92 g (approx.)
Diameter: 26.2mm
Height: 65.6mm
Advantages of 26650 lithium batteries
1. The 26650 lithium battery has overcharge performance: After standard charging, the battery's initial state is measured. When the battery is in normal condition, it is charged at a 3C current to 10.0V, and then switched to constant voltage charging until the cutoff current of 0.01C is reached. The battery's appearance is observed. Result: No fire or explosion.
2. The 26650 lithium battery has over-discharge performance: After standard charging, the battery's initial state is measured. When the battery is in normal condition, it is discharged at 0.5C to 0V. The changes in the battery's appearance are observed. Result: No fire or explosion.
3. Difficult to short-circuit externally: After the battery is charged to standard condition, measure its initial state, place it in an explosion-proof enclosure, and directly short-circuit its positive and negative terminals (total circuit resistance not exceeding 50mΩ). The test ends when the battery temperature drops to approximately 10°C below its peak temperature. Observe the battery's temperature and appearance changes. Result: No fire or explosion.
Disadvantages of 26650 lithium batteries
Because the 26650 lithium battery has a limited range of applications and its performance has been superseded by the 18650 lithium battery, many manufacturers no longer produce this type of battery.
Which is better, 26650 lithium batteries or 18650 lithium batteries? It's impossible to give a direct comparison; it depends on the application. For example, 18650 lithium batteries are widely used in lighting fixtures, industrial lithium battery packs, power tool batteries, electric bicycle batteries, and power lithium battery packs. 26650 lithium batteries, on the other hand, are more commonly used in integrated solar street light lithium battery packs, energy storage stations, and solar energy storage batteries.
