Lead-acid battery charging method
The charging voltage remains constant all the time, which is called constant voltage charging method, or constant voltage charging method for short. Since the constant voltage charging starts to the later period, the power supply voltage remains constant, so the charging current is quite large at the beginning of charging, greatly exceeding the normal charging current value. However, with the progress of charging, the terminal voltage of the battery increases gradually and the charging current decreases gradually. When the terminal voltage of the battery is equal to the charging voltage, the charging current is reduced to the minimum or even zero. Thus, the advantage of constant voltage charging method is that it can avoid excessive charging current at the later stage of charging, resulting in the loss of active material on the electrode plate and electric energy. However, its disadvantage is that at the beginning of charging, the charging current is too large and the volume of the electrode active material changes and shrinks too fast, which affects the mechanical strength of the active material and causes it to fall off. However, in the later stage of charging, the charging current is too small, so that the active material in the depth of the electrode cannot get charging reaction, resulting in long-term insufficient charging and affecting the service life of the battery. Therefore, this kind of charging method is generally only applicable to the special occasions without power distribution equipment or charging equipment is simple, such as the car battery charging, no. 1 to no. 5 dry battery type small batteries are charged using equal voltage charging method. When the battery is charged by equivoltage charging method, the required power supply voltage: 2 for each single battery of acid battery. 4 to 2. About 8V, alkaline battery each single battery for 1. 6 to 2. 0 v.
3) constant voltage charging with fixed resistance
A method adopted to remedy the defect of constant voltage charging. In other words, a resistor is connected in series between the charging power supply and the battery, so that the current at the initial stage of charging can be adjusted. However, sometimes the maximum charging current is limited, so as the charging process progresses, the battery voltage increases gradually, but the current almost becomes linear attenuation. Sometimes two resistance values are used, at about 2.4v, to convert from low resistance to high resistance to reduce venting.
4) phase equal current charging method
Based on the characteristics of constant-current and constant-voltage charging methods, the battery USES a large current at the initial stage of charging, changes to a smaller current after a period of time, and then changes to a smaller current at the later stage of charging. That is, the method of constant-current charging with different current in different stages is called the stage-constant-current charging method. Phase constant current charging method can be generally divided into two stages, but also can be divided into multiple stages.
The phase constant current charging method requires short charging time and good charging effect. Due to the change of charging to a smaller current in the later charging period, the scouring of the active material on the electrode plate by bubbles is reduced and the shedding of the active material is reduced. This kind of charging method can prolong the service life of the battery and save the electric energy. Generally, the first stage of the battery is charged at a rate of 10h, and the second stage is charged at a rate of 20h. The length of each stage of charging time, the specific requirements and standards of various batteries are not the same.
5) floating charging method
Intermittent use of the battery or only in the ac power failure to use the battery, the charging mode is floating charge. The floating charge method is generally used to charge the stationary batteries used in some special occasions. The advantages of the floating charging method mainly lie in that it can reduce the gas extraction rate of the battery and prevent overcharging. At the same time, because the battery is supplied in parallel with the dc power supply, when the power is used in large current of the electrical equipment, the battery will output large current instantaneously, which is helpful to stabilize the voltage of the power supply system and use the electrical equipment normally. The disadvantage of floating charging method is that individual batteries are not balanced and undercharged, so it is necessary to carry out regular balanced charging.
Quick charge
1) fast charging method with fixed current and fixed period
The characteristic of this method is that the battery is charged by a pulse charging current with a constant current amplitude and a constant period. In the charging process, the charging current and its pulse width are not affected by the charging state of the battery. Therefore, it is an open-loop pulse charging. This charging method is easy to make the battery full of capacity, but if you do not increase the protection device to prevent overcharge, easy to cause a strong overcharge, affect the service life of the battery. In this charging method, depolarization measures are added throughout the charging process, but such fixed depolarization measures are difficult to meet the requirements of the whole charging process.
2) constant current and constant air rate pulse charging and discharging depolarization fast charging method
The characteristics of this charging method are: in the whole charging process, the amplitude of charging current pulse and the outlet rate of the battery remain unchanged. At the beginning of the charging process, the charging current is slightly lower than the initial receiving current of the battery. In the charging process, because the acceptable current of the battery gradually decreases, after a period of time, the charging current will exceed the acceptable current of the battery, so the battery will produce more gas, and the air output rate will increase significantly. At this point, the gas detection element can send out a control signal in a timely manner, forcing the battery to stop charging and discharge for a short time. In this way, the polarization within the battery disappears quickly, so that the air rate can always be maintained at a lower predetermined value. There are such schemes abroad. Due to the lack of gas sensors in China, this method is rarely studied.
3) constant current and constant voltage pulse charging and discharging depolarization fast charging method
This charging method is characterized by constant large current charging, to charge to a certain voltage (equivalent to the voltage of the outlet point of the battery), stop charging and large current (or small current) discharge depolarization, and then charge again with a constant large current, according to this, charging and discharging process alternately. The frequency of discharge pulse increases with the increase of charge, and the width of charge pulse decreases with the increase of charge. When the charge amount and discharge are basically equal, it means the battery is fully charged and the charging will be stopped immediately.
According to this method, there are many schemes to realize fast charging of battery at home and abroad. In this method, there is no depolarizing measure at the initial stage of charging. After adding depolarizing measures, the charging pulse width decreases continuously, which makes the average charging current drop faster and extends the charging time.
4) constant current boost voltage pulse charge discharge depolarization fast charging method
This method is an improvement of the fast charging method of constant current and constant voltage pulse charge discharge depolarization. It is charged at a constant current (such as IC). When the battery voltage reaches the outlet voltage of charging (single cell voltage 2.35 ~ 2.5v), stop charging and discharge (such as discharge current 2 ~ 3C, pulse width of 1ms), and then charge again. After the discharge depolarization pulse is added, the charging control voltage (the voltage at the outlet point) is tracked by the integrator step trapezoid to accelerate the charging speed and increase the degree of charging. Other and constant current constant voltage method is the same.
5) constant voltage and constant frequency pulse charging and discharging depolarization fast charging method
The characteristic of this method is that the voltage amplitude of the charging pulse remains constant. As the charging process progresses, the electromotive force of the battery gradually increases, the amplitude of the charging current gradually decreases, the frequency of the charging pulse current is constant, and there is a discharge depolarization pulse added between the two charging pulses.
6) terminal voltage and charging and discharging frequency selection pulse charging discharge depolarization fast charging method
The characteristic of this method is that the charge and discharge pulse frequency is selected according to the polarization of the battery in the charging process, and the terminal voltage of the battery is limited to the preselected value in the later charging period, so that the air output rate is limited to a certain allowable value.
7) adapt to the whole process of depolarization pulse charging and discharging depolarization fast charging method
The characteristics of this method is that, in the charging process is timely and depolarization of discharge pulse, before discharge pulse charging current after recovery, is used to detect the depolarization effect, return to charge a certain depolarization effect, otherwise depolarization discharge again, until you reach the requirements of the depolarization effect return to charge, in this way, can adapt to extreme measures to the whole process. This method can effectively restrain the amount of gas precipitation in a very small number.
Ideal charging
China's conventional charging system is an unreasonable charging method forced to be adopted in the absence of understanding of the charging law. The disadvantages of conventional charging methods are long charging time, low efficiency, large air output, low utilization rate of battery and complex charging management system. There is a certain contradiction between the backwardness of this charging system and the universality of battery application. Therefore, in the field of charging, it is necessary to strengthen the understanding and research of charging laws, and gradually explore a set of fast and good charging system, so as to make the battery adapt to the needs of economic development of various departments and the needs of national defense construction.
1) three-stage charging method
The phase constant current charging method is used to charge aviation batteries. The constant current two - stage charging method is used in general acid aviation batteries. Alkaline air battery adopts constant current two-stage charging method or constant current one-stage charging method. However, this charging method is far away from the charging current acceptance curve in the middle stage of charging, so three-stage charging method is better.
Three-stage charging method is a combination of two-stage equal current charging method and constant constant voltage charging method. Constant current is used at the beginning and end of charging, and constant voltage is used at the intermediate stage. After a period of time, the battery is charged at a constant voltage. When the current decays to a predetermined value, the battery is transferred from the second stage to the third stage. The advantages of the three-stage charging method are as follows: it avoids the situation that the initial charging current of the constant-voltage charging method is too large and the later charging current is too small, which is closer to the acceptance rate curve of the charging current than that of the two-stage constant current charging method in the middle stage. This kind of charging method reduces the amount of gas produced by charging, and the charging is complete, thus prolonging the service life of the battery.
