Repair of lead-acid battery plate softening
2022 Jul 28 By admin 0 comment

The vulcanization of the battery plate occurs in the negative plate, and the softening of the plate occurs in the positive plate.

  1. Characteristics of plate softening

The softening of the battery plate refers to a phenomenon in which the active material on the surface of the positive plate falls off due to various reasons. It has many features in common with the vulcanization of battery plates. Its main feature is that it directly leads to a decrease in the capacity of the battery. After charging with water, black-brown substances are precipitated. These substances are the active substances that fall off the positive plates.

  1. The reason for the softening failure of the plate

The reason for the softening of the battery plate is basically the same as the reason for the vulcanization of the plate. For example, the high current discharge and deep discharge of the battery are not only the cause of the vulcanization of the negative plate, but also the main cause of the softening of the positive plate. Practice has proved that charging and discharging with C/10 current is beneficial to the service life of the battery, so C10 is called the standard charging and discharging current of lead-acid batteries. In terms of batteries for vehicles, electric bicycles are generally equipped with 10A-h batteries, and electric motorcycles are generally equipped with 20Ah batteries. In practice, electric bicycles are mostly driven by a single person, and overloading is rare, while electric motorcycles are more common. Generally speaking, the battery of an electric motorcycle is damaged more, mainly because the discharge current of the battery is large after it is loaded, which causes the positive plate to accelerate softening and damage.

Therefore, the softening problem of the positive plate of the electric motorcycle battery is much more prominent than that of the electric bicycle battery.

In addition, vehicles use batteries with multiple cells in series, and the currents in the series circuit are equal everywhere. In this way, when the capacity of a certain cell of the battery becomes smaller, if the current of the normal battery is still used to discharge, it is obvious that this single cell is running at high current discharge. And the state of deep discharge will inevitably soften the positive plate of the single battery, which will eventually lead to the failure of the entire battery to be used normally.

  1. Maintenance and prevention of plate softening failure

In principle, lead sulfate is formed on the positive plate of the battery when it is discharged, and lead dioxide is formed when it is charged. Because lead dioxide is relatively loose, especially after a crystalline layer is formed on the surface, it is easy to fall off the positive plate if it is subjected to strong vibration or strong current charging to generate strong airflow. In theory, the lead dioxide active material of the positive plate cannot be repaired after falling off. In the actual scrapped batteries, most of them are caused by the softening failure of the positive plate.

The above shows that the key to avoiding softening of the positive plate of the battery is prevention.

When the positive plate of the battery is mildly softened in the early stage, remedial maintenance can be carried out to a certain extent, and early detection and rescue should be carried out. The earlier the detection, the more timely the maintenance, the better the effect.

When the positive plate is slightly softened, it can be repaired by changing positive and negative pulses, that is, using the pulse repairing instrument mentioned above. However, the negative discharge pulse is required to be large enough and wide enough to create a local weak acid environment; the positive pulse needs to be charged in a step-by-step manner. The next negative discharge pulse is used for material preparation, which forms a way of discharging one charging three, which can enhance the performance of the active material of the positive plate and overcome the softening of the plate.

To prevent the plate from softening, deep discharge and high current discharge should be avoided from the source.

In addition, the prevention and maintenance features of plate vulcanization are also applicable to plate softening, which can be used as a good reference.

In general, the prevention and maintenance of the softening of the plate is to prevent the lead dioxide of the positive plate from falling off in large quantities, and to strengthen the combination with the grid, and not to block the fine holes of the positive plate.