How a Single 18650 Battery Charged and Discharged

After connecting the charger to the mobile phone and socket, the voltage is adjusted by the resistance to enter the voltage comparator at a smaller value and output a rating, which is the normal charging of the mobile phone. When the phone is full of electricity, there is a voltage greater than the other end of the voltage into the voltage comparator, which outputs 0V. At this time, the relay absorbs and holds the iron, disconnecting the circuit and realizing automatic power off.

Lithium type 18650 is a lithium battery that is commonly used in electronic products and is often used as a core in laptop batteries. The definition of its model is: such as the 18650, that is, the battery has a diameter of 18mm, a length of 65mm, and a cylindrical type battery.

Lithium cobalt acid

Single section nominal voltage is generally: 3.7 V[ 1]

The charging voltage is generally: 4.20 V-4.3 V / 4.35 V[ 2]

The minimum discharge termination voltage is generally: 2.75 V

Maximum charging termination voltage: 4.20 V(new large-capacity 18650 charging termination voltage of 4.30 V or 4.35 V for Sanyo, Samsung, LG, etc., and 4.20 V for Panasonic)

Diameter: 18 ± 0.2 mm

Height: 65 ± 0.2 mm

Capacity: 13 years can achieve a maximum of 3400 mAh(Matsushita 3400 MAH)

At present, the largest manufacturers of this type of lithium battery in the world are Sanyo(which has been acquired by Panasonic), Panasonic, Samsung, and Sony.

Lithium iron phosphate

Single section nominal voltage is generally: 3.2 V

Charging voltage is generally: 3.6 V

The minimum discharge termination voltage is generally: 2V

Maximum charging termination voltage: 3.65 V

Diameter: 18 ± 0.2 mm

Height: 65 ± 0.2 mm

Capacity: smaller than the 18650 of lithium cobalt acid, common 1500mAh

lithium iron phosphate and lithium cobalt phosphate have the following advantages:

1: Safer, overflush does not cause explosion, leakage of fluid

2: Longer life, normal use energy circulation more than 1,000 times

3: Larger rate, 2C charge 10C discharge, will not burn, explosion, leakage, will not affect life

However, lithium iron phosphate version 18650 monomer voltage, mostly used for high-current electrical appliances. The powered cylindrical lithium-ion battery is mainly 26650 because it has a larger capacity than the 18650.

4: Operating temperature: -20 °C -50 °C, optimal operating temperature is 20 °C -40 °C, similar to the comfortable temperature of the human body

The 1,8650 core used in notebook computers usually has a capacity of 2200mAh(mA), which can be interpreted as: powered by 3.7 V voltage, 2200mA(mA) current, and can use 1 hour(four). The higher specification capacity is 2400mAh and 26000mAh(most of the Sanyo cores, most of Sony's notebooks use 26000mAh specifications).

The following is an example of the common 3.7 V/2200mAh core.

The commonly referred to three-core cell is a battery pack formed by three 18650 cores in series. The final marking parameter of the battery pack is 11.1 V/2200 mAh. 11.1 V = 3.7 V × 3, the output current is unchanged when connected in series.

There is also a standard 10.8 V, that is, a single core has a voltage drop that causes the total voltage to decrease.

The popular netbooks on the market are mostly batteries of this specification.

Two and four core batteries have two situations: four series and two series of two combinations.

The final marking parameters for the four series batteries are: 14.8 V/2200mAh. 14.8 V = 3.7 V × 4, the output current is still 2200mA in series.

The two strings of two, that is, four cores, are divided into two groups. After two series, they are connected in parallel. The final marking parameter of the battery pack is: 7.4 V/4400mAh. 7.4 V = 3.7 V × 2 and the output current is 4400mA = 2200mA × 2.

The medium-sized notebook(12.1 inches, 13.3 inches, etc.) on the market has more batteries of this specification.

Six-core batteries are generally three series and two combinations, that is, six cores are divided into two groups of three, and three and three are connected in series and then connected in parallel. The final marking parameter of the battery pack is 11.1 V/4400mAh. 11.1 V = 3.7 V × 3 with a total capacity of 4400mAh = 2200mAh × 2.

Some high-specification notebooks use six-core batteries.

Of course, there are more than six cores of batteries, such as nine cores and so on.

Capacity discrimination

Electrical power consumption is calculated at "degree", 1 degree = 1000 Wh(watt-hour). However, the laptop battery has a small amount of electricity and it is obviously unreasonable to measure it with "degree", so it is now commonly used internationally as "Wh"(watt-hour, that is, one-thousandth of a degree).

W = Pt, in which W, P, T are the symbols of "energy", "power" and "time", respectively, and their units are usually "Watew", "Pt" and "s".

For example:

W = Pt = 1W * 1s = 1J, which means that a watt of electrical appliances consumes 1 Joule of energy in one second.

W = Pt = 1 kW * 1h = 1 kWh, which means that a one-thousand-watt appliance consumes energy in one hour.

P = UI, where P, U, I are the symbols of "power", "voltage" and "current", respectively, and their units are usually "Watew", "V" and "Ampere A".

For example:

P = UI = 220V * 0.18 A = 40W, which means that the power consumption of a light bulb attached to 220V AC is 40W

W = Pt = 40W * 1h = 0.04 kWh, indicating that the light bulb consumes 0.04 degrees within an hour

If U is replaced with E(which represents the electromotive force, which is the ability of the battery to carry electricity, usually in volts V), IE W = Pt = EIt, we can know the battery capacity. The data marked on the battery is usually mAh at Milliamp, which is the unit of current I * time H, indicating the amount of charge. If a core is marked as 2200mAh, which is 2.2 Ah, by W = UIt = 3.7 V * 2.2 Ah = 8.14 Wh, we can know the capacity of the core.

Look at the battery capacity of the laptop, not the mAh behind it, but the Wh.

Notebook makers are clearly marking the capacity of their cells on batteries, in accordance with air laws.

In general, the Sony core is a green black head with a battery capacity of 2400mAh ~ 26000mAh. Sanyo electric core red skin green head capacity of 2400mAh, red skin light blue head power of 26000mAh.

The 18650 core is distinguished by the color of the cover. Japanese Yashinuo, Huangtou 195mah; Blue head 2000mAh; Red head 2200mAh; Light blue head 2600 mAh; Purple head 2800mAh; Yellow head(charging cut-off voltage is 4.35 V) 3000 mAh; Green head 2400mAh.

The page contains the contents of the machine translation.