The charging control methods of lead-acid batteries are
    1, constant current charging
    2, constant voltage charging
    3, current limiting constant voltage charging
    The charge of the battery is calculated and controlled by 1.2-1.3 times the discharge of the battery, and the temperature cannot exceed 45℃ when the battery is charged.

    After the battery is put into use, it must be charged and discharged regularly. The purpose of charging is to restore the storage capacity of the battery in time to meet the needs of the electrical equipment. The purpose of discharge is to test the battery capacity parameters in time and promote the activation reaction of the electrode active substance. The charging and discharging status of the battery will directly affect the electrical performance and service life of the battery. At present, there are many ways to charge the battery, and choosing a scientific and reasonable charging method will greatly improve the maintenance effect of the battery.
1 Common charging methods for batteries
1) Constant current charging method
    In the charging process, the charging current always remains unchanged, which is called constant current charging method, referred to as constant current charging method or equal current charging method. In the charging process, due to the gradual increase of battery voltage, charging current gradually decreased, in order to keep the charging current from decreasing due to the increase of battery terminal voltage, the charging process must gradually increase the power supply voltage to maintain the charging current is always unchanged, which requires a higher degree of automation for charging equipment, generally simple charging equipment can not meet the constant current charging requirements. Constant current charging method, in the case of the maximum allowable charging current of the battery, the greater the charging current, the charging time can be shortened. Considering the time, it is advantageous to adopt this method. However, if the charging current remains unchanged in the late charging period, at this time, because most of the current is used for electrolysis on the water, the electrolyte has too many bubbles and appears to boil, which not only consumes electric energy, but also easily makes the active material on the plate fall off in large quantities, the temperature rise is too high, resulting in plate bending and rapid decline in capacity and early scrapping. Therefore, this charging method is rarely used.
2) Constant voltage charging method
    In the charging process, the charging voltage always remains unchanged, which is called constant voltage charging method, referred to as constant voltage charging method or equal pressure charging method. Since the constant voltage charging starts to the later stage, the power supply voltage always remains certain, so the charging current is quite large at the beginning of charging, which greatly exceeds the normal charging current value. However, with the progress of charging, the terminal voltage of the battery gradually increases, and the charging current gradually decreases. When the terminal voltage of the battery and the charging voltage are equal, the charging current is reduced to the minimum or even zero. It can be seen that the advantage of constant voltage charging method is that it can avoid excessive charging current in the late charging period, which will cause the active material of the plate to fall off and the loss of electric energy. However, the disadvantage is that at the beginning of charging, the charging current is too large, the volume of the electrode active substance changes and contracts too fast, affecting the mechanical strength of the active substance, causing it to fall off. In the late charging period, the charging current is too small, so that the active material deep in the plate can not be charged, forming a long-term charge shortage, affecting the service life of the battery. Therefore, this charging method is generally only suitable for special occasions where there is no distribution equipment or charging equipment is more simple, such as the charging of the battery on the car, and the charging of the small battery from No. 1 to No. 5 dry battery is charged using the isobaric charging method. When the battery is charged by the isobaric charging method, the required power supply voltage is about 2.4 ~ 2.8V for each battery of the acid battery and about 1.6 ~ 2.0V for each battery of the alkaline battery.
3) Constant voltage charging with fixed resistance
    A method used to remedy the shortcomings of constant voltage charging. That is, a resistance 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 gradually rises, and the current almost becomes a straight line attenuation. Sometimes two resistance values are used, at about 2.4V, to convert from low resistance to high resistance to reduce outgassing.
4) Phase equal current charging method
    Combining the characteristics of constant current and constant voltage charging method, the battery uses a larger current in the initial stage of charging, uses a smaller current after a period of time, and uses a smaller current in the later stage of charging, that is, the method of constant current charging with different currents in different stages is called the stage constant current charging method. Phase constant current charging method, generally can be divided into two stages, can also be divided into multiple stages.
    Phase equal current charging method requires short charging time and good charging effect. Due to the use of smaller current charging at the later stage of charging, this reduces the erosion of the bubble to the active substance of the plate and reduces the fall off of the active substance. This charging method can extend the service life of the battery, save energy, and charge thoroughly, so it is currently a commonly used charging method. Generally, the first stage of the battery is charged with 10h rate current, and the second stage is charged with 20h rate current. The length of charging time at each stage, the specific requirements and standards of various batteries are not the same.
5) Floating charging method
    Batteries that are used intermittently or are used only in the event of an AC power outage are charged by floating charge. Some fixed batteries used in special occasions are generally charged by floating charging method. The advantages of floating charging method are mainly to reduce the gas extraction rate of the battery and prevent overcharging. At the same time, because the battery is powered in parallel with the DC power supply, when the electrical equipment uses large current, the battery will output large current instantaneously, which helps to stabilize the voltage of the power system, and the use of electrical equipment uses electricity normally. The disadvantage of floating charging method is that the individual battery charge is unbalanced and insufficient, so it is necessary to carry out regular balanced charging.
2 Fast charging method for batteries
1) Fixed current and fixed period fast charging method
    The characteristic of this method is that the battery is charged with a pulse charging current with constant current amplitude and constant period, and a discharge pulse is depolarized between the two charging pulses to improve the charging acceptance capacity of the battery.    During the charging process, the charging current and 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 the protection device to prevent overcharging is not added, it is easy to cause strong overcharging and affect the service life of the battery. In this charging method, although the whole charging process is added with depolarization measures, but this fixed depolarization measures are difficult to meet the requirements of the whole charging process.
2) Fixed current fixed gas rate pulse charging discharge depolarization fast charging method
    The characteristic of this charging method is that the amplitude of the charging current pulse and the gas output rate of the battery remain unchanged throughout the charging process. At the beginning of the charging process, the charging current is slightly lower than the initial acceptance 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 more gas will be produced in the battery, and the gas output rate will increase significantly. At this time, the gas detection element can send a control signal in time to force the battery to stop charging and discharge for a short time. In this way, the polarization inside the battery quickly disappears, so that the gas output can always be maintained at a low predetermined value. At present, there are such programs abroad. Due to the lack of gas sensing elements in China, this method is rarely studied.
3) Constant current and constant voltage pulse charging and discharging depolarization fast charging method
    The characteristic of this charging method is that the constant high current is charged, and when the voltage is charged to a certain voltage (equivalent to the voltage of the battery outlet point), the charging is stopped and the high current (or small current) discharge is depolarized, and then the constant high current is charged, so that the charging and discharging process is carried out alternately. The frequency of the discharge pulse increases with the increase of the charge, and the width of the charge pulse decreases with the increase of the charge. When the charge amount and discharge amount are basically equal, the battery is fully charged and the charging ends immediately.
    According to this method, there are a variety of schemes at home and abroad to achieve rapid battery charging. In this method, there is no depolarization measure at the initial stage of charging. With the addition of depolarization measures, the width of charging pulse decreases continuously, which makes the average charging current drop faster and prolonging the charging time.
4) Constant current boost voltage pulse charging discharge depolarization fast charging method
    This method is an improvement of the fast charging method of constant current and constant voltage pulse charging and discharging depolarization. It is charged with a constant current (such as IC), when the battery voltage reaches the charging outlet point voltage (single cell battery voltage 2. 35 ~ 2.5V), stop charging and discharge (such as discharge current 2 ~ 3C, pulse width of 1ms), and then charge... . After the discharge depolarization pulse is added, the charging control voltage is adjusted by using the integrated device step ladder to accelerate the charging speed and improve the filling degree. The other is the same as the constant current and constant voltage method.
5) Fixed voltage and fixed 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, and with the charging process, the electromotive force of the battery gradually rises, the charging current amplitude gradually decreases, the frequency of the charging pulse current is constant, and the discharge depolarization pulse is added between the two charging pulses.
6) Terminal voltage and charge and discharge frequency select pulse charge and discharge depolarization fast charging method
    The characteristic of this method is that the frequency of charge and discharge pulse is selected according to the polarization of the battery charging process, and the terminal voltage of the battery is limited to the pre-selected value in the late charging period, so that the gas output is limited to a certain allowable value.
7) Adapt to the whole process of depolarization pulse charging and discharging depolarization fast charging method
    The characteristic of this method is that the depolarization discharge pulse is added in the whole charging process in a timely manner, and the depolarization effect is tested before the charging current recovers after the discharge pulse, and the depolarization effect is reached and then the charge is returned, otherwise the depolarization discharge is carried out again, and the charge is returned until the depolarization required effect is reached. In this way, the depolarization measure can be adapted to the whole process. This scheme can effectively restrain the amount of gas precipitation within a small value.
3 The ideal charging method of the battery
    China's conventional charging system is an unreasonable charging method that is forced to be adopted in the absence of understanding of the charging law. The disadvantages of the conventional charging method are long charging time, low efficiency, large air output, low utilization turnover of the battery, and complicated charging management system. There is a certain contradiction between the backwardness of this charging system and the universality of battery applications. Therefore, in the field of charging, it is necessary to strengthen the understanding and research of the charging law, and gradually explore a set of fast and good charging system, so that the battery can adapt to the needs of economic development of various departments and the needs of national defense construction.
1) Three-stage charging method
    At present, the phase constant current charging method is used to charge the aviation battery. General acid aviation battery adopts constant current two-stage charging method. Alkaline aviation 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 the three-stage charging method is better.
    The three-stage charging method is a combination of two-stage constant current charging method and constant constant pressure charging method. Constant current is used at the beginning and end of charging, and constant voltage is used in the middle stage. Battery in the initial charging with a large current, after a period of time to change to a constant voltage charging, when the current decays to a predetermined value, from the second stage to the third stage. The advantage of the three-stage charging method is that the constant voltage charging method avoids the situation that the charging current is too large at the beginning and the late current is too small, which is closer to the charging current acceptance curve than the two-stage equal current charging in the middle stage. This charging method reduces the amount of charging output, charges thoroughly and prolongs the service life of the battery.