What is the charging voltage of the lithium battery of the mobile phone?

3.7V lithium battery needs to have a charge and discharge protection board. If the battery has no protective plate, and has only about 4.2V charging pressure. Because lithium battery ideal voltage is 4.2 V, full charge over 4.2V may damage the battery. Charging in this way also needs to check the battery charging status.

Have protection board can use 5 v (4.8 to 5.2), computer USB5v or cell phone 5 v battery charger.

Cell phone lithium battery voltage is 4.2 v.

Cell phone lithium battery voltage characteristic:

Cell phone lithium battery at the same time of extend battery life, the best rechargeable battery voltage is not greater than 4.2 V, excessive discharge at the same time also affect the service life of the cell phone lithium battery.

According to the cell phone lithium battery characteristics, had better use constant current/constant voltage linear pattern to use battery, small current charging, when the battery voltage 3 v or higher, in the constant current charging to 4.2 v, to constant voltage charge, when the current is less than the charger set minimum current, in slowly trickle charging, battery saturation to effectively protect the battery under the condition of charge, however, have to lengthen the service life of the cell phone lithium battery.

Generally is 5 V output of the charger to recharge the battery, and nominal voltage of battery is 3.7 V, usually after a full charge is about 4.2 V, to pay attention to not charge.

12 V battery voltage: 3 section 12.6 V, 4 series of 16.8 V.

【 】 in detail:

1, floating. Refer to the online work while charging. This approach often used in standby power occasion. Not less than 12 FuChong electricity, high too much affect the circuit work. So, floating, voltage of 13.8 v.

2, charging circuit. Refers to restore the full charge capacity of battery, full of, constantly open charger measurement, generally at about 14.5 v, the highest no more than 14.9 volts. Disconnect the charger after 24 hours, usually at about 13 v to 13.5 v. it take about a week after the 12.8 to 12.9 v. The difference between different cell specific voltage value.

The nation lithium ion batteries charging current is 02. C - 1 C, 100 ah battery charging current can be 20 a - 100 a.

3.7 V for lithium ion batteries conventional discharge voltage platform, also is the nominal voltage;

4.2 V for lithium ion battery charging voltage limit, higher than this voltage is easy to damage the battery.

Battery capacity with AH commonly (ampere hour), another is the CELL plate (unit) a few watts (W).(W/CELL) 1. AH (ampere hour), defined in 20 hours as a standard. For example 7 ah battery is refers to the continuous discharge current of 0.35 A, time for 20 hours. Battery capacity is the unit of "mAh", Chinese name is ma (in measuring large capacity batteries such as lead-acid batteries, for convenience, generally by "Ah", Chinese name is, 1 Ah = 1000 mAh).If the battery rated capacity is 1300 mAh, if in 0.1 C for battery capacity (C) the discharge current of 130 ma to battery, the battery can last work for 10 hours (1300 mAh / 130 ma = 10 h);If the discharge current is 1300 ma, the power supply time is only 1 hour (the actual working hours due to the actual capacity of the individual difference of the battery have some differences).3.7 v and 4.2 v is their rated voltage values such as: a section of the dry cell voltage is 1.5 v.

Theory is is possible, but to look at this lithium battery pack the protection of the board under the road whether current of 100 a;

Lithium battery monomer voltage of 3.7 v is index according to voltage (and the average voltage of lithium batteries,)

Lithium battery discharge voltage of 3.00 v, middle voltage 3.7 v, full of voltage is 4.2 v

A, lithium battery and nickel cadmium, nickel metal hydride rechargeable battery:

Lithium ion battery negative extremely graphite crystal, the anode is usually lithium oxide. When rechargeable lithium ion has the positive to the negative movement and embeds graphite layer. When discharge, lithium ion from graphite crystals inside the cathode surface moves to the anode. In the process of the battery charging and discharging lithium always appear in lithium ion form, rather than the form of metal lithium. So this battery is called lithium-ion batteries, lithium batteries for short.

Lithium battery has: small size, large capacity, light weight, no pollution, single section high voltage, low self-discharge rate, cell cycle times more advantages, such as, but more expensive. Nickel cadmium battery because of low capacity, self-discharge is serious, and there is pollution to the environment, are being phased out gradually. Ni-Mh batteries with higher price performance ratio, and does not pollute the environment, but only monomer voltage 1.2 V, and restrictions on the scope of use.

Second, the characteristics of lithium battery:

1, have a higher energy than energy than weight, volume;

2, high voltage, single section lithium battery voltage of 3.6 V, is equal to three nickel cadmium or nickel metal hydride rechargeable batteries in series voltage;

3, self-discharge stored for a long time, it is the battery's most prominent superiority;

4, no memory effect. Lithium battery does not exist nickel cadmium battery memory effect, so the lithium battery without before discharge,

5, long service life. Under normal working conditions, lithium battery charge/discharge cycles is greater than 500 times;

6, can quick charge. Lithium battery can usually use 0.5 ~ 1 times the capacity of charging current, charging time to 1 ~ 2 hours;

7, can freely parallel;

8, because the battery does not contain heavy metals such as cadmium, lead, mercury, on the environment pollution-free, is contemporary the most advanced green battery;

9, high cost. Compared with other rechargeable batteries, lithium battery price is more expensive.

Three, the internal structure of lithium battery:

Lithium batteries usually have two features: cylindrical and rectangular.

Inside the battery adopts spiral winding structure, with a very fine permeability and strong polyethylene film interval between positive and negative isolation material. The anode including composed of lithium cobalt oxide and lithium ion collector and current collector composed of aluminum film. Negative collected by flake carbon material of lithium ion anode and copper current collector composed of thin film. Inside the battery charger has organic electrolyte solution. Equipped with a safety valve and PTC element, the battery in the abnormal state and the output short circuit protect cells from damage.

Single section of lithium battery voltage of 3.6 V, it is impossible to infinite capacity, therefore, will be a single section often lithium battery series, in parallel processing, in order to meet the requirements of different occasions. String 5

Four, lithium battery charge and discharge requirements;

1, lithium battery charge: according to the structure characteristics of lithium battery, charging termination voltage should be 4.2 V, can't overcharge, otherwise it will for the anode of lithium ion to take away too much, and make a battery scrap. The charging and discharging the demand is higher, can be used for constant current, constant voltage charger to charge. Usually constant current charging 4.2 V/holiday turn to constant voltage charging, when constant voltage charging current dropped to 100 ma, should stop charging.

Charging current (mA) = 0.1 ~ 1.5 times the battery capacity (such as 1350 mAh battery, the charging current can be controlled between 135 ~ 2025 mA).Conventional charging current can choose at about 0.5 times the battery capacity, charging time is about 2 ~ 3 hours.

2, lithium-ion battery discharge:, due to the internal structure of the lithium battery is discharging lithium ion can't all to move to the positive, you must retain part of lithium ions in the cathode, in order to make sure the next rechargeable lithium ion can flow in channel. Otherwise, the battery life is reduced. In order to guarantee the graphite layer after discharge in the left part of the lithium ion, to strictly limit discharge termination of the lowest voltage, that is to say, the lithium battery can't discharge. Discharging termination voltage of 3.0 V/usually section, the lowest not less than 2.5 V/section. The time of the battery discharge and the battery capacity has the size of the discharge current. The battery discharge time (hours) = battery capacity/discharge current. Lithium battery discharge current (mA) should not be more than three times as many battery capacity.(such as a 1000 mAh battery, the discharge current should be strictly controlled within 3 a) or you will make a battery damage.

Lithium-ion battery pack that is sold on the market at present are sealed with forms of the charge and discharge protection plate. As long as the good control outside of the charge and discharge current.

Five, the lithium battery protection circuit:

Two lithium battery charge and discharge protection circuit is shown in figure 1.By two field-effect tube and special protection integrated block of S - 8232, charging control pipe FET2 and over discharge control FET1 series in the circuit, controlled by protection IC and monitor the battery voltage, when the battery voltage up to 4.2 V, over charging protection tube FET1 cut-off, stop charging. To prevent misoperation, it is generally in the external circuit with delay capacitance. Under the battery discharge conditions, when the battery voltage to 2.55 V, a discharge control tube FET1 cut-off, stop supply power to the load. Overcurrent protection is in when have large current flows through the load control FET1 make its deadline, stop to load discharge, the purpose is to protect the battery and the field effect tube. Over-current detection is to use the field effect tube conduction resistance test for the resistance, to monitor its voltage drop, stop discharge when the voltage drops more than set value. Generally there plus time delay circuit in the circuit, to distinguish between surge current and short-circuit current. The circuit is functional, reliable performance, but strongly professional, and application-specific integrated block is not easy to buy, amateur is not easy to copy.

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