Hello
My question is about initial charging and formation On small and laboratory scale,
With two cells and H2SO4 electrolyte.
How many stages are required for initial charging?
It was mentioned in an article that :"The formation process is based on three successive charging steps: charging at a rate of 0.1 C for 3 h, at a rate of 0.14 C for 24 h and again at a rate of 0.1 C for another 3h"
But when we tested this formation, our electrochemical tests like cyclic voltammetry had a problem.
We have a power supply. For applying formation, we inflate the voltage to infinite and then change the current.
It is told that each 15 grams positive active material in a lead acid battery requires 1Ah capacity.
So at the first time we weigh positive active material and then calculate capacity. It is called "C".
According to the article that I mentioned, we start formation: first stage 0.1 C for 3h, 0.14 C for 24 h and again 0.1 C rate for 3h.
Actually I don't know where our problem is.
Articles often low mentioned about initial charging and formation of lead acid batteries do not explain well
Thank you
Dear Morvarid
You explained the formation procedure, but what was the problem?
As you sed, 15 g of active material is 1 Ah, means for example that 15 mg is 1mAH right. So how to do you apply gym current with 100 microampere for 3 hours this means a chance chargeof 0.1C. After that you apply an imposed current of 140 microamper mean a step of charge of 0.14 C for 24 hours and finally you impose a current of 100 microampere for 3 hours. Now if you have a mass equal to m so you do (m/15)*1AH= total capacity, now the imposed current Is
1st-(m/150) ampere for 3 hours.
2nd-(m*0.14/15) ampere for 24 hours.
3rd-(m/150) ampere for 3 hours.
The electrochemical method to do that is chronopotentiometry.
I hope this is useful for you.
Good luck.
Also as you know maybe your starting material is tribasic lead sulfate or lead sulfate according to that not. All current is used for making lead dioxide there is also oxygen evolution reaction (0.1C*3+0.14C*24+0.1C*3)~4time the Capac