Tubular gel battery
There are distinct advantages of lead-acid battery technology compared to lithium-ion battery & other electrochemical systems. Affordability, reliability, recyclability and safety are key issues in choosing the right battery for a particular application and lead-acid batteries will score highly in these categories. There is, however, a drawback when using conventional flooded lead-acid batteries for deep cycle applications. This is the maintenance required in topping up the batteries due to water loss by gassing. In many applications, like in traction battery applications, there is a need to completely recharge a battery in a limited time frame.
This normally will require higher voltages which in turn leads to the breakdown and loss of water from the electrolyte through gassing. These flooded lead-acid batteries will require topping up with water, creating inconvenience and costs and in large installations which often requires expensive extraction equipment. There are also other disadvantages, particularly with transport, storage and disposal. The liquid acid in the lead-acid battery is classified as a hazardous material for transport. Whilst this is not considered a problem within the industry, which operates using safe and proven procedures, it is much better to immobilise the acid to prevent spillages.
Tgel Battery lead acid battery - how the acid is immobilized in Gel and AGM batteries
One fortunate consequence of acid immobilisation is that it creates the ability to recombine the hydrogen and oxygen gases which are produced from the breakdown of water inside the battery when on charge. There are two principal methods for acid immobilization:
Use of absorptive glass mat which holds the acid in place called AGM VRLA batteries &
The other, adding a fine silica powder to make a gel as in a Tubular gel lead acid battery
Both methods, although very different, achieve the goal of immobilisation in gel and agm batteries.
They also provide the added benefit of recombining the gases released on charge to reform water, thereby removing the need for the water-addition maintenance procedures mentioned earlier for flooded lead-acid batteries. Out of these two methods, the use of silica-gelled electrolyte is universally recognised as the best solution for deep discharge tubular gel lead acid battery designs. There are two main reasons for this: the first is that the use of gelled electrolyte allows a tubular positive lead plate to be used, which is recognised as providing the best deep cycle properties for lead-acid batteries. The second reason is that the stratification of acid associated with deep discharges and limited-voltage recharging without gassing is avoided, in tubular gel battery.
Tubular gel lead acid battery - main advantages
These are significant advantages if you have deep cycle requirements as in solar battery applications. The use of tubular lead plate batteries provides the most robust lead-acid tubular gel batteries design with the highest deep cycle capability of all lead-acid designs. The resistance to stratification, in tubular gel battery is of great benefit in many applications which operate at partial state of charge (PSoC) such as standby power, UPS and SolarEnergy clean environment markets.
The main advantages of the tubular gel batteries are the absence of the need to top up your battery. So why is the lack of topping up, such an advantage? You have to consider the problems of maintaining lead-acid batteries in remote locations with difficult access. In flooded batteries, if you forget to top up with water they can dry out and fail. The cost of maintaining these flooded batteries with regular monthly or quarterly visits can be very high. For a business, this can make an installation uneconomical.
Tubular gel batteries - maintenance-free
The other side of this expensive coin is the maintenance, particularly in commercial environments where equipment reliability is key to providing a reliable and regular service. If batteries powering essential equipment fail due to lack of maintenance, the ramifications for credibility and reputation can be considerable. For the private user, it can be equally frustrating. For example, having to access installed batteries and obtain distilled water sometimes is not so easy, not to mention keeping a log and records for possible warranty claims. And of course, there is the situation where we are simply extremely busy and accessing and maintaining batteries can be a really time draining exercise.
There are also those clean environments where charging batteries can produce damaging or even explosive fumes, particularly in confined spaces. This is relevant for batteries used in computer backup and medical equipment applications where batteries are kept in cabinets or inside complex and sensitive equipment. To remove fumes from charging batteries it is sometimes necessary to install expensive extraction equipment to remove explosive hydrogen gas and corrosive acid fumes from confined spaces in cabinets or equipment.
Tubular gel batteries - no leakages
There are also clean environment applications as in hospitals and food storage. In these environments smells and corrosive gases could contaminate food or damage human health. Looking again to the consumer applications, the last thing they need is a battery in their home, garage or solar power bank, which is producing explosive gases or corrosive fumes on when on a charge.
Gel batteries are sealed batteries. They do not leak. There is no risk of acid leakages. They are maintenance-free. It classifies them as non-hazardous for transportation, by rail or air. Terminals do not have any corrosion.
Tubular gel batteries - Long life
There is no risk of leakages in a tubular gel battery since the electrolyte is in gel form. Since they cannot leak the tubular gel battery can be used in any orientation. If the tubular gel battery falls or breaks, there will be no acid spills. There will be no environmental damage caused because of accidental spillage of acid like from a flooded battery. Tubular gel battery are resistant to vibration & shocks. They don’t release explosive gases like in large battery bank installations of flooded batteries.
Tubular gel batteries - recover from deep discharge quickly
They recover faster from a deep discharge or if left discharged over a long time. They have a huge life span & comes maintenance free!
The only disadvantage of a Tubular gel battery is the initial cost compared to to the flooded battery or the AGM battery. The tubular gel battery usually cost 30 to 40% more than the normal batteries. This cost though appears to be more, easily is offset by the Return on Investment as explained above. Other than the cost there are only advantages!
Tubular gel batteries - Key designs
So just how do this combination of tubular lead plate and GEL electrolyte work? To understand we have to look at several elements which contribute to the battery’s properties, these are:
An electrolyte which is immobilized as a GEL to ensure non-spillage and also to enable the transportation of hydrogen and oxygen released on charging (which is held inside the battery under pressure) to be recombined to form water. The benefit of immobilization extends further, it prevents the creation of strata of acid with different densities within the cells, called Acid Stratification.
In flooded batteries and sometimes AGM VRLA designs, denser gravity sulfuric acid produced at the lead plates during charge can drop to the bottom of the cell by gravity, leaving the weaker specific-gravity acid at the top. Batteries in this condition suffer early failure from battery sulfation, premature capacity loss (PCL) and grid corrosion. Tubular Gel batteries overcome this issue by the ‘gellification’ of the acid & do not suffer from acid stratification – a serious mode of failure in very tall cells needed to be kept vertical. Microtex have a Tubular gel battery-making plant imported from Germany and use high-grade imported fumed silica to give uncompromising life and performance to their tubular gel battery.
Absorbent glass mat or AGM batteries use a glass mat like a sponge to retain the sulfuric acid inside the cell. There is no free sulfuric acid & is generally called a starved electrolyte condition battery. The AGM types of battery uses flat lead plates for the positive & the negative electrodes, which unlike tubular positive plates are more prone to corrosion. AGM batteries have a lesser life compared to tubular gel types of battery.
Tubular gel types of battery uses the tubular design of the battery lead plate. This is essentially a pressure cast lead alloy spine instead of a gravity casted grid, which is covered by a fabric gauntlet then filled with the positive active material (PAM). This can be either a dry lead oxide powder or a wet lead oxide slurry. A tubular gel battery design of plate has a couple of advantages: the first is that it has a higher surface area in contact with the sulfuric acid to give better material utilization (as much as 60%). (As seen in the pic above). The second reason is that tubular gel types of battery and 2v cells have the highest cycle life of the entire lead acid battery range.
I purchased gel cell batteries because I leave my solar energy system unattended for months on end. It seems to be working still 4 years later. I have no idea if my Renogy gel cells are tubular. I guess I’ll know in a few years if they are still working with good capacity and health. Thanks for the interesting write up.
posted 2 months ago
Happy to read your comment, Thanks! & hope they last a long time!
We have seen a 9-year life on our batteries in Australia.