Cause and Analysis of Lead-Acid Battery's Deformation or Damage

Most of LONEN LED flashlights, lamps and lanterns use built-in sealed lead-acid battery which can be recycled over 300 times. This type of battery has relative longer life-span and bigger capacity, most of all, the lower price makes it popular in the market. Except for these advantages, the lead-acid battery needs to be used in a proper way due to its nature and character, like it should be charged fully at least once every three months for the battery mainetance to insure the battery lifespan. On the contrary, improper usages may cause deformation or damage of the battery and even lead to explosion. Now let's see how does the deformation happens.

Battery Deformation Process 

The battery shell material is plastic ABS, which should not be out of shape when used in 45 degree circumstance. After the battery completely discharges, we use a charger to charge the battery. And when it’s charged to 80%, the charging enters into high voltage charging process, and the oxygen will start to be separated from the positive plate. Then the oxygen turns to negative through the microporous of the AGM partition. Oxygen recombination happens on the negative plate. Heat is generated during the reaction. And when the charging reaches 90%, oxygen's generating becomes faster and more hydrogen will be produced on the negative. It produces more and more gas and will exceeds the safety valve. The valves then opens and gas will escape with water.

The more battery recycles, the more water will reduce. As a result, the specific heat capacity of the battery will badly decrease and battery will rise very quickly in temperature. After the water loss, the battery's AGM separator shrinks and the adhesion between it with the negative plate turns worse, and resistance increases, more heat will be produced during the process of charging and discharging. After that, the dissipation of the heat generated inside the battery only occurs through the battery shell. If the heat dissipation is less than the heat production, temperature will rise. In that way, massive oxygen on the positive will go through the channel and react on the negative surface, which produces a lot of heat and the temperature will increase to 80 degree and finally the battery shell becomes deformed and damaged.

Battery Deformation Reason 

There are many reasons on account of the bulge of the battery:

A. During the charging process, especially during the end of charging, it will produce massive explosive gas inside the battery. If the air hole on the battery filler plug is blocked at this time, the gas cannot be evacuated in time and will accumulate in the battery. Under the high pressure, the battery will bulge and deform in the end.

B. When the charging current of the battery is too large or charging time too long, the electrolyte temperature will increase rapidly and generate large amounts of gas. The active material on the battery plate will loose and fall off, which causes the battery to blow up.

C. When the battery plate becomes vulcanizing, the single voltage and electrolyte temperature will rise rapidly when charging, which will easily cause the battery to bulge.

D. When starting electric motor, battery should be within a short period of time the motor to provide a lot of current (generally is 20 ~ 40 A). If the continuous starting time is too long, such large starting current will cause the battery internal violent chemical reaction and may lead to explosion if the gas is not evacuated in time.

E. Electrolyte's high liquid viscosity or dries up can also lead to deformation of the battery.  

How to prevent the storage battery from deformation? 

To prevent the battery from bulge or crack, first of all, no spark is allowed when using the battery. Thus the battery is required to installed firmly and the welding of the battery plate should be guaranteed.

Secondly, the battery filler cap must be screwed up and tightened and the vent hole should be dredged regularly, in order that the gas generated during the operating of the battery can easily exhaust through the vent hole.

Last but not least, avoid over charging and discharging of the battery.