26650 lithium battery
1. Definition of 26650 lithium battery
The 26650 lithium battery is a type of cylindrical lithium battery, suitable for special equipment, medical equipment, instrumentation, power tools, transportation and logistics, security monitoring, surveying and mapping and other fields. 26650 lithium battery size: diameter is 26mm, length is 65mm.
2. Advantages of 26650 lithium battery
26650 lithium battery has low energy density, low self-discharge rate, stable charge and discharge performance, no memory effect, no decomposition when exposed to heat, high safety performance, long life cycle, high voltage, can be used in series or parallel to form a 26650 lithium battery pack, environmentally friendly Pollution.
3. Single 26650 lithium battery
26650 lithium batteries are mainly divided into ternary materials and lithium iron phosphate materials.
Voltage
INR26650 lithium battery nominal voltage 3.6V, full charge voltage 4.2V, discharge cut-off voltage: 3.0V
IFR26650 lithium battery nominal voltage 3.2V, full charge voltage 3.65V, discharge cut-off voltage: 2.0V
Safety performance test of 26650 lithium battery
1. Overcharge performance
After standard charging of the battery, measure the initial state of the battery. When the battery state is normal, charge it to 10.0V with a current of 3C, and then transfer to constant voltage charging to stop when the cut-off current is 0.01C. Observe the change in the appearance of the battery. Result: no fire, no explosion
2. Over discharge performance
After standard charging of the battery, measure the initial state of the battery. When the battery is in normal state, discharge it to 0V at 0.5C. Observe the change in the appearance of the battery. Result: no fire, no explosion
3. External short circuit
After the battery is standard charged, measure the initial state of the battery, and place it in an explosion-proof cover to directly short-circuit its positive and negative electrodes (total resistance of the circuit is not greater than 50mΩ). The test ends when the battery temperature drops to about 10°C lower than the peak temperature. Observe the temperature and appearance changes of the battery. Result: no fire, no explosion
4. Hot box test
Measure the initial state of the battery. After standard charging, the battery is placed in an oven, and the temperature is increased to 130±2°C at a rate of (5±2°C)/min and kept for 30 minutes. Observe the change in the appearance of the battery. Result: no fire, no explosion
5. Fall
Test the initial capacity of the battery. After standard charging, measure the initial state of the battery. Drop the test battery from a position with a height of 1m (the lowest point) to the concrete floor vertically and horizontally, requiring two drops. Result: no fire, no explosion
6. Heavy impact
A steel rod with a diameter of 15.8mm is placed in the middle of a fully charged battery; then a hammer with a weight of 10Kg is freely dropped from a height of 1.0m to the upper part of the battery. Result: no fire, no explosion
7. Squeeze test
The battery core is placed between the two extrusion surfaces of the extrusion equipment, the cylindrical battery core axis is parallel to the extrusion surface, and the pressure is gradually increased to 13kN, and the pressure is maintained for 1 min. Result: no fire, no explosion
26650 lithium battery charging
1. Precautions for charging 26650 lithium battery
The basic requirements for charging the 26650 lithium battery are the specific charging voltage and charging current at each stage, and some other auxiliary functions are added to improve the battery life;
In order to ensure the stable and reliable operation of the battery and prevent the interference of transient voltage changes, the internal delay circuit should be designed with overcharge, overdischarge, and overcurrent protection to prevent transient interference from causing instability;
The factors that affect the safe and effective charging of the 26650 lithium battery are voltage, current and temperature. Therefore, these three factors should be taken care of and controlled in the charger design.
2. Can the 18650 battery charger charge the 26650 battery?
You can use the 18650 lithium battery charger to charge the 26650 lithium battery, but do not use it for a long time. Because the voltage platform of the 18650 lithium battery charger is relatively high, the 18650 lithium battery voltage platform is 3.6V and 4.2V, and the 26650 lithium battery voltage platform It is 3.2v and 3.6V. Therefore, long-term use will cause damage to the 26650 lithium battery.
How to buy 26650 lithium battery?
26650 lithium batteries are widely used in the fields of electric tools, lighting, wind energy storage, electric vehicles, toys, instruments, UPS backup power supplies, communication equipment, medical equipment and lights. What should we pay attention to when purchasing 26650 lithium batteries?
1. Appearance and production process
Look at the appearance refers to look at the appearance, workmanship, size and craftsmanship of the 26650 lithium battery. The advanced technology is very comfortable to the touch. After polishing, the rubber oil polishing material has a good touch and strong insulation performance.
2. Capacity identification
The 26650 lithium battery without a clearly marked capacity is probably a garbage battery reassembled with inferior battery cells or recycled battery cells. There are many cheap 26650 lithium batteries on the market. They are made from recycled or disassembled battery cells. Although they are cheap, they have short life span and unstable quality. Careless use may damage the equipment or even explode.
3. With or without protection board
The characteristics of the 26650 lithium battery determine that the 26650 lithium battery must be equipped with a protective plate to prevent the 26650 lithium battery from being overcharged, over-discharged and short-circuited. The 26650 lithium battery without the protective plate will deform, leak, and explode. Danger. In the fierce price competition, various battery packaging factories seek lower-priced protection circuits, or omit this device at all, making the market flooded with 26650 lithium batteries that are dangerous for explosions.
4. Flat and pointed ends
The 26650 lithium battery has a flat head and a pointed head. The difference between the two is one with a protective plate and the other without a protective plate.
Flat-head 26650 lithium battery: without protective plate.
Pointed 26650 lithium battery: with a protective plate, because the top of the protective plate protrudes, the protruding part is the protective plate.
Under normal circumstances, I recommend buying pointed batteries to ensure compatibility with more devices and uses. Generally, the positive and negative electrodes of electric appliances are designed with springs, which can be extended and contracted, and can be used regardless of the pointed and flat head batteries.
But if the flat-head battery is used in series, the positive electrode of the flat-head cannot touch the negative electrode of another battery.
