The battery regeneration process
Regeneration of lead-acid batteries.
What is a lead-acid battery? The plates of spongy lead (pol) and lead dioxide (pol+) are bathed in dilute sulfuric acid (density 1.24 to 1.30) with demineralized water. A charged battery consists of these plates and sulphuric acid discharged, of the same plates, part of which is converted into its amorphous form into lead sulphate and into low density sulphuric acid, almost water. The filler converts amorphous lead sulfate into sulfuric acid and replenishes the plates. At the end of the charge, gas, oxygen and hydrogen can be released through the electrolysis of water. Thus, lowering the level of electrolytes.
Amorphous lead sulfate crystallizes when there is time, it is embedded on and in the plates of the battery to form islands. Chronic stress is an important contribution. Once lead sulfate is crystallized, it is no longer converted to sulfuric acid at the time of charging, it is too stable and a charger is inefficient, the battery is called "sulfated". This can happen very quickly if a starter battery is left empty, 36 hours is enough to crystallize amorphous lead sulfate, or five to ten years slower if a well-treated battery is used.
The second factor for the degradation of the battery capacity is the oxidation of the lead plates, with the age of the battery being one of the main causes this time as well as a chronic electrolyte deficiency. Even for a well-treated battery, the mark of 15 to 20 years is difficult to pass, except in special cases. Regeneration does not work with an oxidized battery.
During regeneration, high-performance controlled electrical impulses are sent. Gradually they break the crystal lattice of lead sulfate, where an ordinary feeder does not work. Lead sulfate is electrolyzed back to sulfuric acid and the plates are refilled. The process takes from 24 hours for a car battery, up to five to ten days for large industrial batteries weighing several tons. The battery returns to its maiden capacity. It is said to be desulphated.
The cost is about a quarter of the price of the new replacement of industrial batteries, a good point for the environment through half of the waste and energy savings through better efficiency of electricity spent on charging. .
The method was validated in 1995 by the Central laboratory for electrical industries for Bureau Veritas. Download the Bureau Veritas report .
Regeneration is economical, ecological and clean
Lead-acid batteries.
Invented by Frenchman Gaston planted in 1859, they have conquered the world ever since. 99% of the batteries produced worldwide are lead-acid batteries. We all have at least one in our diesel or gasoline vehicles. The industry uses a lot of it in its forklifts to overcome power outages caused by inverters, solar energy storage and many other applications. Almost all lead used to make them comes from recycling old batteries, lead is a toxic metal, never get rid of a lead-acid battery by throwing it into the wild .
The nominal voltage of a lead battery is 2 V (2.15 V for a fully charged battery). To achieve higher voltages, the 2 V elements are assembled in series (in a single file). Therefore, the name of the battery, we should use the term electric accumulator battery, but the word battery has definitely.
New technologies appear, but are not ready to dethrone the old lead-acid battery, which will remain the queen in her field for a long time to come. Lithium batteries are five times more expensive and lithium is very rare and very toxic on our planet. Nickel-cadmium batteries are almost banned because of the toxicity of cadmium. NiMH batteries have a hideous memory effect, which is not present in lead-acid batteries, and a small number of charge / discharge cycles. Other technologies are likely to emerge as the lithium battery suffers and especially sodium ions .
Two digits mark a lead battery: its voltage in volts (V) is twice as high as the number of 2 V cells that make up the battery, and its capacity in ampere hours (Ah). This capacity depends on the amount of electricity needed for the discharge. The discharge time is preceded by the letter C, C10 means for a discharge in 10 hours. Traditionally, the capacity of a starter battery is given in C20, traction in C5 and Solar in C100. For example, a battery of 1000 Ah in C100, only about 800 Ah in C10, 660 Ah in C5 is and will rise to 1100ah in C240.
A third digit with CCA prefixed, specific to starter batteries in the data In a (amps). This is the maximum intensity that the battery can provide for a certain number of seconds, measured by different standards, in (European) SAE (American) and others less common with us.
Three categories of batteries.
Starter battery. They are able to supply a large current in a very short time. The lead plates of which they are composed are thin and numerous. They cannot be discharged more than 20% without reducing their service life, and must be recharged as soon as possible after discharge. We find them in combustion engine vehicles. Nominal density of the electrolyte of 1.28 to 1.30.
Slowly discharging batteries (also called traction batteries). They are designed for up to 80% discharge before charging. They are called "bicycles", depending on the technology they can withstand 500 to 1500 charging / discharging cycles. The lead plates are thick and consume water. DIN designation: EPZs, British EPzB, electrolyte nominal density 1.28 to 1.30
Stationary batteries, a variant with slow discharge. They are designed for low maintenance, so that very little water is supplied. Two types in this category, those necessary for the provision of emergency power, which is important in a short period of time (telecommunications, inverters, etc.) and those that accept charging cycles, deep discharges (80%), solar energy, wind energy, isolated sites. DIN-designation: OPzV, OPzS, suffix, solar, type, deep discharge, nominal density of the electrolyte is often lower, 1,24, but more amount of electrolytes. With the same capacity, the volume of the batteries, whose electrolyte has a lower density, is higher.
Three Technologies.
With lead open, access is possible to compensate for water loss by adding liquid. There is a closed launch variant, it is said to be" maintenance-free", a certain amount of water is supplied to compensate for the inevitable losses, that is almost programmed obsolescence. These batteries are available in starter, slow discharge (train), stationary and Solar available.
AGM (absorbed glass mat). The electrolyte is absorbed into a kind of glass fiber blotting (borosilicate). Their internal resistance is small and suitable for the start and has a certain cycling ability. The gaseous development of oxygen and hydrogen recombines in water. They are waterproof and maintenance-free. A safety valve allows degassing to prevent accidental pressurization of the coil. VRLA: Valve Regulated Lead Acid
Gel. The electrolyte is always sulfuric acid and silica gel. Their internal resistance is higher and must be slowly loaded and unloaded with excellent cycling ability, even withstanding high temperatures. Not very suitable for the beginning. They are waterproof and maintenance-free. They are also VRLA.
These three battery technologies are regenerated!
Charge.
Two phases. At the beginning of the charging process, the current slowly increases the battery voltage (so-called absorption phase). After a threshold, 2.4 V (floating phase) for a 2V cell, 14.4 V for a 12V battery, there is electrolysis of water and thus fluid loss, the battery "boils". The charging process is therefore continued at an imposed charging voltage of 2.4 V per cell. A balancing phase is desirable from time to time at 2.6 V per 2V cell, at low intensity to avoid heating, but only with open batteries there is a water loss that must be compensated by adding demineralized water. To avoid this loss, it is necessary for closed batteries (gel, AGM and maintenance-free) that the charger at the charging end limits the voltage to less than 2.4 V per cell. But sending 2. 4V from the beginning would cause a too large, destructive charge for the battery. Choosing a charger is the guarantee for the durability of the batteries.
What you should remember.
The water is filled only with demineralized water, never acidic.
For maintenance-free AGM and gel batteries, use a specific charger, never overcharge it, the battery will dry out and lose permanently.
Depending on your usage, choose your battery type, start, slow discharge (cycle), stationary or stationary (solar).
Pay careful attention to the electrolyte level of the open starter and less critical traction batteries with stationary and solar batteries that consume less water. Only charge the water with a charged battery. The volume increases naturally during charging.
Charge your batteries completely, even if this means that the open starter and the traction batteries or the stationary batteries become a little overcharged to avoid a water loss that is easily compensated.
What not to do, take precautions.
In the case of a discharged open lead battery, keep the electrolytes to a minimum if necessary by adding demineralized water until the plates are covered, no more. The electrolyte volume naturally increases during charging, with the risk of acid leaking from the container. At the end of the charging process, fill the level, if necessary, always with demineralized water.
Never add sulfuric acid to a battery. If the electrolyte density is too low after a full charge and a balancing load, this is a sign of sulfation. Think of regeneration instead. The only case in which the addition of acid is desirable is after an electrolyte loss due to overflow, for example. Acid evaporates not only water can do this, its electrolysis is the second cause of electrolyte loss.
Never pour water into the acid, there is immediate heating and great risk of corrosive and dangerous splashes. Treat acids only if they are protected by an apron, gloves, mask, boots and other necessary and appropriate personal protective equipment (PPE). All this is resistant to corrosive chemicals.
The batteries provide electric current, with the inherent risk of electric shock. Only authorized and protected persons are able to work in an environment where electric accumulator batteries are available.
Batteries must develop in a ventilated environment, the release of high-explosive oxygen and hydrogen is normal and not dangerous. Watch out for the flames, do not smoke.
0 Comments