The voltage amplitude of the charging pulse remains constant. With the progress of charging, the battery electromotive force gradually increases, the amplitude of the charging current gradually decreases, the frequency of the charging pulse current is constant, and a discharge depolarization pulse is added between the two pulses.

    Under normal conditions, the lead-acid battery is charged with a current less than the discharge (less than 10% of the rated capacity) as the conventional charging, and the charging mode greater than this current is called rapid charging. In general, conventional charging is adopted, and fast charging is only used in special emergency situations.

Outgassing volume and outgassing rate

    The gas output is an important sign of the degree of chemical reaction in the charging process of battery. The gas output refers to the sum of the gas weight when the pressure of the gas released from the positive and negative plates reaches 0.1MPa during the whole charging process of the battery; The outgassing rate refers to the weight of gas emitted from the positive and negative plates per unit time at a certain stage of charging under the pressure of 0.1MPa.

    During the charging process, the gas will make the electrolyte flow out from the pores of the electrode plate, affect the chemical reaction of the battery and reduce the charging speed. When the outgassing rate is too high, the generated gas will make the active material fall off and affect the capacity and service life of the battery. In order to prolong the service life of the battery and improve the charging speed, the air outlet rate should be reduced as much as possible.

temperature rise

When lead-acid battery is charged rapidly, it will produce high temperature rise and shorten battery life. Generally, the temperature rise should be controlled within 45 ℃.

life

It refers to the number of charge and discharge cycles that the battery can reach when charging rapidly. The lead-acid battery adopts fast charging, and its service life is lower than that of conventional charging.

General method of fast charging

Constant outgassing rate charging method

    The gas sensor is used to detect the rate of gas precipitation from the battery, so as to control the charging current. At the beginning of charging, charge with high current. When the gas generated in the battery reaches a certain value, send a control signal to the charging circuit according to the change of sensor parameters to reduce the charging current to maintain a constant air outlet rate. This method cannot be used for charging sealed or maintenance free batteries. large

The current charging time shall be within 30 minutes.

    The charging current is controlled by detecting the amount of electricity charged into the battery. When charging with this method, it is necessary to master different charging states in the charging process, so as to control the charging current.

Constant voltage charging method

Fast charging is performed when the charging voltage is determined and maintained at a constant value. At the initial stage of charging, the battery voltage is low and the charging current is large. With the progress of charging, the current gradually decreases. The method is simple and the control system is easy to implement.

No load constant voltage charging method

    Temporarily interrupt the charging current and quickly measure the voltage before resuming charging to keep it at no-load constant voltage. The voltage does not include the internal resistance voltage drop of the battery. This method is suitable for batteries with different structures, different service life and different charging states.

Constant current constant period fast charging method

    The battery is charged with a pulse charging current with constant current amplitude and constant cycle, 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 its pulse width are not affected by the charging state of the battery. This method is easy to fill the battery, but it is easy to cause overcharge if the anti overcharge protection device is not added.

Fast charging method with constant current and constant gas discharge rate

    During the whole charging process, the amplitude of charging current pulse and the air outlet rate of battery remain unchanged. The method is to send a control signal in time through the gas sensor to force the battery to stop charging and discharge for a short time. The polarization inside the battery will disappear soon, and the air outlet rate will always maintain a low value.

Fast charging method with constant current and constant voltage

    Charge with a constant high current. When it is charged to the outlet voltage of the battery, stop charging and discharge, and then charge with a high current. The charging and discharging process is carried out alternately. The width of discharge pulse increases with the charge amount, and the charging pulse width decreases with the increase of charge amount. When the charging capacity and discharge capacity are basically equal, it indicates that the battery is basically full, and the charging is ended immediately.

Fast charging method with constant voltage and constant frequency

    The voltage amplitude of the charging pulse remains constant. With the progress of charging, the battery electromotive force gradually increases, the amplitude of the charging current gradually decreases, the frequency of the charging pulse current is constant, and a discharge depolarization pulse is added between the two pulses.

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