DESC:FORM-2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(SECTION 10, RULE 13)

TITLE
“WOVEN GAUNTLET FOR HIGHER LIFE OF A BATTERY”

APPLICANT(S)
EASTMAN AUTO AND POWER LIMITED, a company organized and existing under the laws of India, of the address, 572, Udyog Vihar Phase-V, Gurgaon, 122016, India

The following specification particularly describes the invention and the manner in which it is to be performed
FIELD OF INVENTION :-
The invention is related to the field of battery. More particularly, the present invention is related woven gauntlet for lead-acid batteries that increases the life of a battery.

Background of Invention :-

In lead-acid batteries, the tubular plate design is totally different from the flat plate in a way that the conducting materials are separated from the mechanically supportive components. The tubular plate is formed with vertical lead rods called as spines, which are connected in parallel with a common top bar forming a current-collector framework and bottom bar for enclosing the spines. The usage of number of spines differs as per the required application. The spines are covered by either a woven or a non- woven material in an individual manner, which are known as gauntlets.

The design of tubular plate delivers faster energy and the electrical capacity is 20% more at least, and longer service life up to 30% more than flat plate. This design is favored for flooded, gel and even AGM batteries. Apart from that, high-tech filling processes have made the design to be more efficient and reliable allowing them to be manufactured at a competitive cost. The active material for the positive tubular plates will be used in either of the two forms: i) powder type and, ii) slurry type. Depending on the battery applications, the usage type will differ. For the slurry type active material, non-woven gauntlets with no visible pores is used for restricting the escape of slurry into the electrolyte. In case of powder type active material, woven-gauntlets with particular porosity is used for the efficient transfer and diffusion of ions into the electrolyte without material shedding.

Two types of crystal phases are present in the positive active mass namely a-PbO2 and ß-PbO2. Alongwith these two phases, amorphous PbO2 will also be present. Based on the two authors, Caulder and Simon, it is explained that the hydrogen in PbO2 produced through electrochemical processes are higher than that are produced through the chemical processes. The presence of hydrogen will be in mobile or adsorbed OH- groups or as H2O molecules. Other hydrogen are firmly attached with the crystal lattice which makes them less mobile. To control this mobility characteristics without the higher water loss, gauntlet with specific requirements were designed by instant invention.

The tubular plate design is commonly used for positive electrodes in batteries that require large capacities. Those plates were also extensively used in traction applications. Previously, Lead alloys with 9 wt% antimony have been used for the grids. These batteries possess excellent rechargeability and a good cyclic performance. Because of their higher mechanical strength, high antimony content was used to be preferred even though they results in high corrosion rate. In the past decades, there was a movement towards less antimony (2 wt%) alloys for reducing the corrosion rates, although it is difficult to cast and process than the traditional design. For gel VRLA batteries, Lead-calcium alloys with higher tin content were also used for tubular plates just because of the beneficial effect of the tin towards the plate design. The tubular plates are also used for batteries up to the capacity of 1000 Ah.

The active material for the positive tubular plates will be used in either of the two forms: i) powder type and, ii) slurry type. Depending on the battery applications, the usage type will differ. For the slurry type active material, non-woven gauntlets with no visible pores will be used for restricting the escape of slurry into the electrolyte. In case of powder type active material, woven gauntlets with particular porosity will be used for the efficient transfer and diffusion of ions into the electrolyte without material shedding.
Gauntlets are preferred in industries because,
• Loss in discharge capacity due to softening and shedding of active materials can be significantly reduced.
• High-porosity can be used with this design and also the uniform current flow over the active material can be seen because of the spines acting as a current- collector.
• Although assembling single tubes on the spines is a time- consuming operation than inserting the whole grid into the insulative layer, the greater rigidity is provided by the physical bond of the single tubes as a multi-tube array during the filling process.
• Lateral movement resulting in the bowing of spines is nearly impossible.
Non-woven cloths are getting attraction because the weaving process is eliminated. However, to achieve the desired bursting strength of woven materials, higher thickness will be considered for non-woven tubes. Because of this, the consumption of the active material will be marginally reduced.
In case of woven cloths, their porosity is suitable for better diffusivity of ions into the electrolyte. Various studies have been done to improve its formation, manufacture, and current-collecting design. But the diffusion is a main thing to be considered for choosing a gauntlet. This is because the smoother flow of ions or electrons is needed for a longer life and the better diffusion characteristics. Hence, the woven gauntlets are used for enclosing the spines in our battery design since they support the essential needs. The woven gauntlets are shown in Figure.1
Therefore, there is a need to provide a woven gauntlet for enclosing the spines structures and prevents the active materials from shedding into the electrolyte.

Summary of the invention :-
Since the active material used in the positive plates are the major concern among the other factors in lead-acid batteries, it is necessary to take the safeguarding measures to help them being away from the contact with the electrolyte. So, the gauntlets are used for enclosing the spine structures and prevents the active materials from shedding into the electrolyte. The porosity and the other parameters of gauntlets have to be clearly defined for the production of batteries for long cycle life and higher efficiency. Those specific parameters have been defined by Applicant herein in the woven gauntlets for a battery with good cycle life and improved efficiency. These gauntlets help the active materials to acts as the active centres for the hydrogen evolution reaction, when get in contact with the electrolyte by diffusion. The gauntlets and the bottom bar were designed in a way to reduce this active material shedding which results in a lower water loss leading to the reduction in efficiency loss. Hence, the parameters for the gauntlets as designed by applicant herein increases the overall efficiency of the battery and also help in providing the better backup characteristics of the battery.

Therefore such as herein described there is provided a woven gauntlet for Lead-Acid type storage batteries comprising multiple individual spine structures having walls and an upper and a lower opening and forming a cartridge belt type gauntlet; wherein said woven gauntlet is configured as enclosing chamber for the end of the spines along with the bottom bar and prevent shedding of the positive active material (PAM) into electrolyte.

In an embodiment, the woven gauntlet have the number of pores is adjusted to the range of 410-450 in the area of 1cm2, which in turn reduces the pore size to an average range of less than 20000 µm2.
Brief Description of the accompanying drawing:-

Figure 1 illustrates the Figure 1: (a) Image of a new woven gauntlet, (b) Magnified image in accordance with the present invention;
Figure 2 illustrates the Spines enclosed within a woven gauntlet (3D Image) in accordance with the present invention;
Figure 3 illustrates the Dimensions of a new woven gauntlet in accordance with the present invention;
Figure 4 illustrates the Pore size check of new woven gauntlets using Single Zoom Microscope in accordance with the present invention;
Figure 5 illustrates the Pore analysis done in Olympus Microscope Imaging at 100x magnification (Dark Field Imaging) (Area considered for imaging: 1 cm2) in accordance with the present invention;
Figure 6 illustrates the Measurements of warp and weft in new woven gauntlets using Olympus Microscope Imaging (Magnification: 200X) (Dark Field Imaging) in accordance with the present invention;

Figure 7 illustrates the Comparison of Pore Size Distribution in old and new Woven Gauntlets in accordance with the present invention;

Figure 8 illustrates the Positive plate with new woven gauntlet filled with positive active material (3D image) in accordance with the present invention;

Figure 9 illustrates the Threads spun by Warp and Weft method in accordance with the present invention;

Figure 10 illustrates the Life cycle comparison of batteries with old and new gauntlets in accordance with the present invention.

Description of the invention :-

As we know that, the water recombination is very important for the enhanced life of a battery. The active materials have been designed to prepare in the way to increase the reactivity with lower water loss. To help them from shedding into the electrolyte, the gauntlets were used for enclosing the active materials. This is because the increased water loss results in the need for higher maintenance of the battery. Also, the regular top-up of the battery will not be required due to the lower water loss. The reduction in the active material shedding makes the flow of ions and electrons becomes smoother enhancing the overall efficiency and product life. Hence, the overheating inside the cell can be escaped restricting the thermal runaway of the battery.

The pore of the gauntlet plays an important role in the diffusion characteristics of the ions between the active materials and the electrolyte. If the porosity is higher, shedding of the active materials is highly possible. Also, if the pores are lesser, diffusion will get reduced affecting the overall performance of the battery. It must be adjusted within the specified range in a particular area. Figure.2 shows the spines enclosed within the woven gauntlets and the pore size tests were done using Single Zoom Microscope as shown in Figure.4.

As shown in Figure.7, the number of pores in the new woven gauntlets has been adjusted to the range of 410-450 in the area of 1cm2, which in turn reduces the pore size to an average range of less than 20000 µm2. This plays a major role, just because of the restricted pore size, the positive active material (PAM) cannot escape from the gauntlets. Diffusivity of the ions is increased and the material loss out of the confined space is reduced since the pore does not pave the way for the particle evolution. Hence, the ionic movement will be smoother because the pathway for their transfer is enhanced because of the control characteristics in the pores as shown in the microscopic examination in Figure.5 & 6.

Table 1: Controlled specifications of the woven gauntlets
S. No Parameters Old Gauntlet New Gauntlet Specification by EAPL
1. Weight loss in 1.3 sp.gr H2SO4 at 70 °C for 24 hrs (%) 0.64 0.53 <0.8
2. Oxidation Resistance in 1.3 sp.gr H2SO4 at 70 °C for 24 hrs (%) 0.67 0.53 <1
3. Bursting strength (kg/cm2) 40 45 35 (minimum)
4. Electrical Resistance (m?) for 10 cm2 area 1.96 1.74 <2.8
5. No. of Pores / sq.cm 358 431 >350
6. Compression Strength (C.S) (kg) 41.3 48 >25
7. Avg. pore size (µm2) 37450.63 16585.715 <20000

From Table.1, electrical resistance is decreased in the newly designed woven gauntlets showing that their conductivity support is good and results in the better ionic transfer. Also, the oxidation loss is reduced in the new gauntlets paving the way for the electrochemical reactions to take place in an improved manner. The weight loss in the acid is also reduced in the newly designed woven gauntlets explaining their resistance towards acid-effect is higher.

As shown in Fig. 8 the positive plate with woven gauntlet filled with positive active material is illustrated. The water recombination is very important for the enhanced life of a battery. The active materials have been designed to prepare in the way to increase the reactivity with lower water loss. To help them from shedding into the electrolyte, the gauntlets were used for enclosing the active materials. This is because the increased water loss results in the need for higher maintenance of the battery. Also, regular top-up of the battery is not required due to the low water loss. The reduction in the active material shedding makes the flow of ions and electrons becomes smoother enhancing the overall efficiency and product life. Hence, the overheating inside the cell can be escaped restricting the thermal-runaway of the battery. Since the porosity of the gauntlet is important, pore size tests were done using Single Zoom Microscope.

As shown in Figure.10, for a battery with new gauntlets at a rated capacity of 200 Ah, a battery reached the cut-off voltage after 795 cycles at 45°C (equivalent to 1987.5 cycles at 27°C). This comparison data shows that the life cycle of the batteries with new gauntlets increased more than 30 % of the batteries with old gauntlets. Also, the graph explains their consistent capacity deliverance and backup characteristics.

LIFE CYCLE TEST PROCEDURE:
1. Discharge the battery @ 400 W till 10.8 V.
2. Charge the battery with 15.00 A till 14.80 V for 9hrs.
3. Repeat the cycling.
4. Test Temperature @ Ambient condition.

Advantages of the woven gauntlet of the present invention:
1. Woven gauntlets act as an enclosing chamber for the end of the spines along with the bottom bar and prevent shedding of the positive active material (PAM);
2. Woven gauntlets are used with the specific porosity to support the diffusion characteristics of ions from the PAM into the electrolyte;
3. Since, the electrical resistance of gauntlets is very low, paving the way for the active materials to carry out the electrochemical reactions inside the system.
4. Since weight loss of gauntlets in the acid is very low, explaining their strength towards the acid effect. Thus, their life can be increased;
5. Gauntlet along with the bottom bar provides clamping for the active material thereby helps in increasing the backup characteristics of the battery;
6. Due to their mechanical stability, mossing can be eliminated which is mainly caused by the shedding of the materials from the active mass;
7. Polyester material is used for the preparation of woven gauntlets by spun yarn using warp and weft method and hence the gauntlets are produced with high tenacity.

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration by way of examples and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
,CLAIMS:We Claim:
1. A woven gauntlet for Lead-Acid type storage batteries comprising multiple individual spine structures having walls and an upper and a lower opening and forming a cartridge belt type gauntlet;
wherein said woven gauntlet is configured as enclosing chamber for the end of the spines along with the bottom bar and prevent shedding of the positive active material (PAM) into electrolyte.
2. The woven gauntlet as claimed in claim 1, wherein the number of pores is adjusted to the range of 410-450 in the area of 1cm2, which in turn reduces the pore size to an average range of less than 20000 µm2.
3. The woven gauntlet as claimed in claim 1, wherein polyester material is used for the preparation of woven gauntlets by spun yarn using warp and weft method.
4. The woven gauntlet as claimed in claim 1, wherein said positive active material for the positive tubular plates is of powder type.
5. The woven gauntlet as claimed in claim 1, wherein the said average pore size of less than 20000 µm2 increases the diffusion characteristics of ions from the PAM into the electrolyte and reduces the material loss out of the confined space the pore does not pave the way for the particle evolution.
Dated this 19th day of May, 2023.

Arghya Ashis Roy
Patent Agent (IN/PA 2346)

To,
The Controller of Patents, The Patent Office
Delhi