Determination of effects of sulphation on lead-acid batteries

In summary: It is white.In summary, the conversation revolves around a project on the effects of sulphation on lead-acid batteries. The main issue is the formation of lead sulphate which crystallises and hinders the flow of electricity. The proposed experiment involves determining the concentration of sulphuric acid before and after the cell activity to see if there is a decrease, indicating the conversion of sulphate ions to lead sulphate. However, it is pointed out that this method may not accurately show the type of sulphate present on the electrodes. Alternative methods, such as using nitric acid or comparing fresh and dead battery electrodes, are suggested. The conversation ends with a discussion on the colors of fresh and lead sulfate electrodes.
  • #1
isaaclimdc
36
0
Hi all,

I'm doing this project entitled "determining the effects of Sulphation on lead-acid batteries", and what it essentially is, is the reason why these batteries lose their effectiveness after being left in a discharged state for a period of time. What happens is lead sulphate is formed from the discharge redox reactions of the lead electrodes in sulphuric acid electrolyte. This lead sulphate crystallises after awhile, and is very insoluble and a nonconductor. These crystallise around the electrodes, hence hindering the flow of electricity.

For my experiment, I have a cell up and running, and I need to find a way to determine whether or not lead sulphate crystallises, and use the "Nernst Equation" to calculate the actual voltage. Can this be done by determining the concentration (by standardisation with borax) of the sulphuric acid before and after the cell activity, and say that if a decrease in concentration is observed, then this amount of sulphate ions were converted to lead sulphate?

Sorry for the long explanation, but this is a really important project for me, so any help is much appreciated.

Thank you,
Isaac.
 
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  • #2
Determining acid concentration should be more or less enough. Depending on the accuracy you may either use titration or just check acid density with hydrometer. As checking battery charge level is (or at least was) quite popular thing to do there were hydrometers already scaled in the sulfuric acid concentration.
 
  • #3
Does the design of my experiment sound feasible to you? It was all made up in my head without expert help, so I was wondering whether everything is valid?
 
  • #4
This is more complicated. PbSO4 is always present in the battery and its presence is absolutely normal. However, usually it is in amorphous form, which can be easily dissolved. Sulfation refers to the process of crystallization - where amorphous lead sulfate is converted into crystalline lead sulfate. Just measuring amount of sulfuric acid you will be not able to tell what kind of sulfate is present on the electrodes. If you will compare concentration of sulfuric acid in fully charged batteries (otherwise identical, but one already broken) you will see the difference in acid concentration - but you will be not able to tell "why". That requires some crystallographic method.
 
  • #5
Thanks for your replies. I understand what you're saying. However now, is there an alternative way for me to show the effects of sulphation in this manner, without the use of complex analytic methods? My teacher suggested the use of nitric acid. How does this work?
 
  • #6
No idea what s/he aims at. Perhaps determination of just lead left?
 
  • #7
Is there really no way else around this.. I really need this experiment to work..
 
  • #8
Could be that "simple" comparison of electrodes from the new and dead battery will work. Just charge the battery and compare the surface. You may try microscope. You may try to scratch some precipitate that covers electrode and analyse it.
 
  • #9
What color is your fresh electrode? It should be red. What color is lead sulfate?
 

1. What is sulphation and how does it affect lead-acid batteries?

Sulphation is a process in which lead-acid batteries develop a layer of lead sulphate on their electrodes, reducing their ability to hold a charge and decreasing their lifespan. This can occur due to overcharging, undercharging, or prolonged storage without being recharged.

2. How can I determine the level of sulphation in a lead-acid battery?

There are several methods for determining the level of sulphation in a lead-acid battery, including measuring the specific gravity of the electrolyte, performing a voltage test, or using a specialized battery tester. These methods can help determine the extent of sulphation and whether the battery is still usable or needs to be replaced.

3. Can sulphation be reversed or prevented?

Sulphation can sometimes be reversed by using a desulphator or applying a high-voltage pulse to the battery. However, prevention is the best approach. This can be achieved by properly maintaining the battery, avoiding overcharging or undercharging, and regularly recharging it to prevent sulphate buildup.

4. How does sulphation impact the performance of lead-acid batteries?

Sulphation can significantly decrease the performance of lead-acid batteries by reducing their capacity and increasing their internal resistance. This can result in a shorter runtime and more frequent need for recharging. In severe cases, sulphation can lead to permanent damage and failure of the battery.

5. Are there any other factors besides sulphation that can affect lead-acid battery performance?

Yes, there are other factors that can impact the performance of lead-acid batteries, such as temperature, age, and overuse. Extreme temperatures, both hot and cold, can affect the chemical reactions in the battery and decrease its lifespan. Older batteries also tend to have reduced performance, and excessive use can cause wear and tear on the battery's components.

Determination of effects of sulphation on lead-acid batteries

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