Plante battery, Roller, forming plates, Charge and discharge.
Now the holiday period is over and different parts of the family have returned to their respective Countries, i can now focus on this project, well sort off!
Okay a few photos of works that i looked at over the Holidays.
Firstly, here is a pic of my Electro Plating stuff, now i know most of you will say, 'what's that got to do with the PLANTE battery'?
As you know we need to form the correct oxide on those lead plates surface, and to improve the surface lead area we are putting 0.5mm wide and 0.5mm deep grooves in the acting/facing surface. This also holds the formed oxide in the chequer pattern we make with the grooves. Ie, a modern method.
However, forming the oxide is a long process of minimum of 30 charge and discharges and reversing polarity before each charge of the battery, after 30 times we can then dictate what will be the positive and negative.
Now over the past 45 years, part of my designing and manufacturing specialised mechanical time pieces for a 300 year life, I electro plate all my brass internal mechanisms, this then protects the brass from corrosion and having to be constantly cleaned.
So, my electro plating equipment is for items up to a 3-litre container size, and I plate in hard Gold, Silver and Rhodium. Yes, i have all the chemicals to do this, but times voltage and amperage and temperature must be within certain parameters or the plating will have poor adhesive performance or not consistent. Forming the Oxide on the lead plates is just the same, however written information on this forming process is minimal, so hopefully using my experience with electro plating I should be able to find a happy formula to form some good stable and well adhered Oxide on those lead plates.
Remember we are turning that first 0.75mm thickness of the lead into mushy oxides. So I need to find a solution that ordinary folk out there can use when they are making their own PLANTE batteries.
CHARGING & DISCHARGING to Form the Oxides.
From my past experiences with simple PLANTE cells and the other limited information that I have I will use these figures to get a reasonable Charge and Discharge regime for forming the Oxides.
Rated Amp hour capacity of our 2.22v cell for the PLANTE battery is defined roughly by surface area and weight of each POSITIVE PLATE ONLY in that cell.
Amp Hour rate.So with our 6 POSITIVE plates of 210mm x 630mm and at 2.24mm thick, we need to know the plate weight and the surface area that we can form to get the amp hour. The calculations are a little ‘wishy washy’ and will need confirming, however a rough guide for our plates for one 2.22v battery of 6 positive plates would be very approximate about, 550 amp hour size.
There are a lot of things happening.Firstly, with a anode plate and a cathode plate, ie one lead plate and another plate facing each other this is called a single cell, the usable voltage of this cell will not exceed more than 2.3 volts, in practice its about 2.22volts.
Secondly, on bare lead when you first fill with acid solution the cell becomes live, the acid solution is fully charged. ie, its specific gravity is up at the appropriate levels this will change as the cell is discharged. Normally its about 1.265 and during discharge it will drop to about 1.150 and the electrolyte will only be 17%. When recharged the battery will rise again to 36% electrolyte and about 1.265 again. As the battery gets old in the normal commercially made modern type batteries, the specific gravity will drop as the internal plates deteriorate and the useful amp hour rates also drop.
For our PLANTE battery it’s the other way around. Our initial Amp Hour rate is not as good as a modern commercial battery, ie only about 1/3rd but over the many years it will be used the battery gets better until eventually all the lead plates internally are just a oxide paste. So we need to hold that oxide as long as we can, and not allow oxide residues to drop down under gravity and short out the cell within the battery itself.
Thirdly, when first filled you will see that the PLANTE Cell is Bi- sexual, ie, put your voltmeter leads on each plate, then remove the leads and swap them around and hay presto it gives voltage the other way around as well.
CHARGING the PLANTE battery.Okay so we need to form the correct oxides to form on the correct plates. So to form correctly for the best attributes for the oxide, we charge at 20% to 23% over the designated, designated voltage for each of our cells is 1.5v volt cell. And at 10% to 13% of the amperage of the calculated rated Amp hour capacity of that cell.
So for our battery we will charge at 2.43volts and at 57amps.
Remember change the polarity for each of the 30 plus charges as you form the plates.
A designated 12 volt battery are normally 6off 2.22v voltage cells, with each 2.22v cell have about 7off 2,22v cells parallel connected to get the Amperage out put up of each 2.22 cells, these 6off are then connected in series to get a 12v battery that when new would give about 13.32volts.
Photo below shows the hand roller materials being assembled. WE MUST ENSURE that NO ferrous/Iron particles get embedded into the lead plates, this would be detrimental to the life of the battery. Hence every metal part of the tool is stainless steel or brass.
Here I am using a simple hand tool, but had to reduce the roller from 55mm wide down to 20mm wide of acting roller as then the pressure required to push into the lead is not severe, at 55mm wide about 45kg was required in down force to operate in one pass. We only want one pass as over passing could mess up the surface so particles of lead could start falling from the lead plate when its in operation, and we do not want that.
The roller itself is stainless steel with 0.5mm wide groove forming ridges and giving a 0.5mm depth with the grooves at 1mm spacings. The roller must be consistently made.
I will probably fit a lead plate thumb screw guide arm and ski, so the roller can be guided precisely on each 20mm wide down the lead plate stroke.
The 5kg weight will sit on the roller tool and therefore give a constant pressure to the roller tool.
Its all a bit variable at present, but hopefully i can get the tool simplified and easier to make for normal folk.
Discharge rates for PLANTE battery plate oxide forming.
Each of the 30 times minimum charge and discharge should be the same rates to form the correct Oxide. And remember the polarity should be reversed on each charge.
On the 31st charge you will then make the positive palates positive from then on.
Discharge should be about 10% of the cell capacity in voltage and amperage.
So for our 2.22volt 550ah PLANTE battery thats, discharged at about 2.442volts and at 55amps.
