FIELD OF THE INVENTION:
The present invention relates to tubular gel valve regulated lead acid batteries (TGEL-VRLA) and particularly to the composition and synthesis of the fumed silica gel electrolyte.
BACKGROUND OF THE RELATED ART:
Lead acid battery has been used widely in many energy storage applications since from its invention. Even though, there are many advantages in other technologies, lead acid batteries are preferred due to their lower cost, safety, Recyclability and lower maintenance.
The valve regulated lead acid batteries are extensively being used in the applications such as uninterruptible power supply (UPS), solar, telecom, power plants etc where continuous maintenance or monitoring of the battery is not possible.
A gel may be regarded as a type of colloidal system behaving as a solid or relatively low elasticity. Various attempts have been made to gel the acidic electrolyte in storage battery cells to eliminate spilling, the need for constant maintenance and for other reasons. No satisfactory gel electrolyte has been produced, however, because batteries containing such gel electrolytes have not had electrical properties as good as those with ordinary liquid electrolytes. For example, their internal resistance is higher and capacity is lower in batteries incorporating a gel electrolyte. Also, the cycling characteristics of batteries containing the gel electrolyte have not compared well with batteries having liquid electrolytes. In addition to these disadvantages, gel electrolytes have had a tendency to shrink after a short time so that the contact between the gel electrolyte and the active mass in the battery cell is soon interrupted. Thus, cracks form in the gel electrolyte allowing air to carry oxygen to the plates or electrodes of the battery, allowing the electrodes to discharge. Furthermore, the initial viscosity of the gel is so great that it has been difficult, if not impossible, to completely fill the electrolyte chamber and the electrode pores with the gel electrolyte.

One such attempt at gelling an electrolyte was disclosed in British Pat. No. 785,848, issued to Robinson on Nov. 6, 1957. This patent discloses the use of fine particles of silica of submicron size, approximately 0.015 micron diameter, mixed with dilute sulfuric acid. The amount of silica in the final mixture is disclosed to be about 12% by weight. However, the problems described above still remain.
Another problem which affects the use of both liquid and gel electrolytes is the need to replace the electrolyte after formation of the cell. Presently, most lead-acid batteries are filled with low specific gravity electrolyte and the electrodes of the batteries are formed by placing a charge on them. After this formation process, the formation electrolyte is dumped out and is replaced with fresh electrolyte having the desired specific gravity. It is well known that if the low specific gravity formation electrolyte were not replaced, the battery would exhibit poor electrical properties.
The formation process is expensive for a number of reasons. Changing electrolyte after charging requires additional labor and time. Even though the formation electrolyte may be recycled, contaminants build up in the electrolyte. Eventually, the electrolyte must be either cleaned or discarded.
It is well known that separator material is placed between electrodes of batteries to prevent electrical shorting. Simultaneously, the separator material must also permit diffusion of electrolyte through its pores and the passage of electric current between the electrodes of batteries to prevent electrical shorting. Simultaneously, the separator material must also permit diffusion of electrolyte through its pores and the passage of electric current between the electrodes. Additionally, the separator material must be stable in the electrochemical environment, i.e., resist deterioration due to exposure to the electrolyte and the chemical reactions taking place on the electrodes. One of the long standing problems in improving batteries has been to make a separator material which optimized those various characteristics.
US4317872A contemplates a gel electrolyte for use in a lead-acid battery. The gel electrolyte includes a silica component having silica particles, means for repelling the particles from each other and for catalyzing the formation of siloxane cross-linkages, and a

sulfuric acid component. Additionally, the present invention includes a lead-acid battery incorporating the gel electrolyte. The lead-acid battery includes a container, a plurality of electrodes substantially enclosed by the container, and the gel electrolyte in a substantial physical contact with the plurality of electrodes.
US9105401 provides that the electrolyte comprises from about 1 wt. % to about 40 wt. % of at least one ammonium salt of an organic acid, from about 0.01 wt. % to about 10 wt. % of at least one acid, from about 0.5 wt. % to about 20 wt. % of inorganic oxide particles, from about 30 wt. % to about 70 wt. % of water, and from about 5 wt. % to about 40 wt. % of at least one secondary solvent. The working electrolyte is in the form of a gel and has a pH value of from about 5.0 to about 8.0 and has a conductivity of from about 10 to about 80 milliSiemens per centimeter, determined at a temperature of 25° C.
In accordance with another embodiment of the present invention, a method for forming a wet electrolytic capacitor is disclosed. The method comprises forming a mixture that comprises an ammonium salt of an organic acid, inorganic oxide particles, an acid, and a solvent system that comprises water; inducing gelation of the mixture so that it exhibits a first phase angle 8 of from about 50° to 90°; placing the gelled mixture into communication with an anode, cathode, or both, wherein the anode comprises an anodically oxidized pellet formed from a pressed and sintered powder and the cathode comprises a metal substrate coated with a conductive polymer; and thereafter, allowing the mixture to further gel to form a working electrolyte that exhibits a second phase angle 8 of from 0° to about 20°, wherein the working electrolyte further has a pH value of from about 5.0 to about 8.0.
CN106229559 discloses a silicate gel electrolyte. The silicate gel electrolyte is prepared from the following components in percentages by weight: 30% to 40% of deionized water, 60% to 70%) of a sulfuric acid solution with the density of 1.5 to 156 g/ml, 1.5% to 2% of nano-fumed silica, 0.5% to 1% of sodium silicate, 0.5% to 1% of ammonium sulfate, 0.5% to 1% of potassium sulphate and 0.15% to 0.2% of ammonia water.
The tubular gel type of valve regulated lead acid batteries is superior to flooded flat plate and tubular batteries in terms of cyclic life, self discharge, stratification and thermal runaway.

But cost of the tubular gel VRLA battery is 5-8% higher compared to other types. Thus there is a need for further improving the cyclic life which compensates this increased cost.
SUMMARY OF THE INVENTION
As said in background of the art, an objective of the present invention is to improve the cyclic life of the tubular gel VRLA battery used in uninterruptible power supply, solar, telecom, power plants applications. This is achieved by introducing the novel composite advanced silica based gel electrolyte in which the concentration of the fumed silica is higher compared to conventional electrolyte.
Another objective of this invention is to derive the process parameters such as electrolyte temperature, specific gravity and mixing speed for making the said electrolyte. The batteries prepared with the said electrolyte composition and process, performs better than conventional electrolyte in terms of cyclic life, electrolyte stratification and charge acceptance.
The batteries also exhibits less water loss, self discharge and completely maintenance free compare to others.
DETAILED DESCRIPTION
The present invention provides composition of a new advanced fumed silica based gel electrolyte and its manufacturing process which is used in tubular valve regulated lead acid batteries. According to the present invention a silica gel electrolyte composition is prepared using fumed silica with 8-9.5 % by weight of the total electrolye, sulphuric acid with 88-89%) by weight, phosphoric acid with 2-3 % by weight and Sodium sulphate with 0.2% by weight.
The fumed silica have the temped density of 40g-60g/ltr with aqueous dispersion of the same shall be between 4% and 7% and with a pH value between 5-7. The specific gravity of the sulfuric acid electrolyte used is 1.12-1.16 with 19% concentration.
Additionally the present invention also provides for a method for preparing the gel electrolyte and a valve regulated lead acid battery incorporated with this electrolyte. The method comprisies the steps of adjusting the specific gravity of the sulfuric acid electrolyte to the desired

concentration at 27°C and then it is chilled at 0-8°C temperature. Then the fumed silica powder is slowly added into the electrolyte keeping the mixer at a speed of 1250-1500 rpm.
First the unformed battery is filled with 1.18-1.24 specific gravity sulfuric acid and then soaked for 2-3Hrs. The battery is thereafter formed by applying a charge current of 10% of the rated capacity for 30-36Hrs. The formed battery is discharged up to the end specific gravity reaches to 1.12-1.16. The acid is then dumped and the above prepared gel electrolyte is filled. Then charge of about 105-110% of rated capacity is applied to activate the battery.
The prepared tubular gel VRLA battery provides maintenance free deep dischargeable high performance at all environmental conditions and replaces present low maintenance Tubular lead acid Battery. The said batteries perform better in terms of cyclic life of around 15-20% than conventional flooded (flat and tubular) batteries. The batteries also exhibit less water loss and self discharge with better oxygen recombination. The following table provide for the specification of Electrolyte and method for preparing the same.
Specification for Tubular GEL Electrolyte Mixing

S.No Tubular GEL Electrolyte Unit Qty
1 Fumed Silica
• Temped Density 40g-60g/ltr
• Aqueous dispersion shall be between 4% and 7%
• PH Value 5-7 % by weight 9
2 Sulfuric Acid
• Density 1.13±0.005
• Concentration 19% % by weight 88-89
3 Phosphoric acid
• Density 1.66±0.005
• Concentration 85% % by weight 2-3
4 Sodium Sulphate % by weight 0.2
Process Specification

5 Mixing Temperature degC 0-3
6 Mixing RPM RPM 900-1000
7 Final Temperature degC <8
8 Viscosity of GEL Electrolyte Cp <20
9 Density of GEL Electrolyte Gm/cc 1.140-1.150
It is to be note that the entire Gel electrolyte mixing will be carried out by maintaining RPM is 900-1000 in the mixture to obtain the viscosity of about 20Cp, the final temperature maintained is less than 8°C . The final Gel Electrolyte specific gravity obtained is about 1.140-1.150 at 8°C being used as a final fill electrolyte before final charging to arrive the product in fully functional
The batteries as prepared according to the present invention perform better in terms of cyclic life of around 10-15% than conventional flooded (flat and tubular) batteries. The batteries also exhibit less water loss and self discharge with better oxygen recombination.
Although the foregoing description of the preferred embodiment of the present invention has shown, described and pointed out the fundamental novel features of the invention, it will be understood that various omissions, substitutions, and changes in the form of the detail of the batteries and method as illustrated as well as the uses thereof, may be made by those skilled in the art, without departing from the spirit of the present invention. Consequently, the scope of the present invention should not be limited to the foregoing discussions, but should be defined by the appended claims.

WE CLAIM
1. A gel electrolyte composition comprises of
fumed silica with 8-9.5 % by weight of the total electrolye, Sulphuric acid with 88-89% by weight, phosphoric acid with 2-3 % by weight and Sodium sulphate with 0.2% by weight.
2. A gel electrolyte as claimed n claim 1 wherein the Sulphuric acid concentration is 19%.
3. A gel electrolyte as claimed n claim 1 wherein the Phosphoric acid concentration is 85%.
4. The method of preparation of the gel electrolyte as claimed in claim 1 in preparation of a battery, wherein the method comprises the steps of
a. adjusting the specific gravity of the sulfuric acid electrolyte to the desired
concentration at 27°C;
b. chilling the same at 0-8°C temperature;
c. slowly adding the fumed silica powder into the electrolyte keeping the mixer at a
speed of 1000-1250 rpm.
5. A method to for preparation the battery as clamed in claim 4 wherein
- the unformed battery is filled with 1.18-1.24 specific gravity sulfuric acid and
then soaked for 2-3Hrs;
a charge current of 10% of the rated capacity for 30-36Hrs is applied;
- the formed battery is discharged up to the end specific gravity reaches to 1.12-
1.16.
dunping the acid and filling the gel electrolyte into the battery;
providing the charge input of about 105-110% of rated capacity to activate the
battery.