DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A METHOD FOR APPLYING SEPARATOR COATING ON THREE-DIMENSIONAL ELECTRODE”

APPLICANT:

E-TRNL ENERGY PRIVATE LIMITED
A company incorporated under the Indian Companies Act, 2013
having address at
Plot No. 08, SY No. 75, Sadaramangala lndustrial Area,
M.D. Pura White Field, Mahadevapura, Bengaluru,
Bengaluru Urban, Pin Code – 560048, Karnataka, India

PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:
FIELD OF THE INVENTION
The present invention relates to a separator coating method. More particularly, the present invention relates to a method for applying separator coating on three-dimensional electrode.

BACKGROUND OF THE INVENTION
A separator is a crucial component in an electrochemical cell that separates the positive and negative electrodes while allowing the flow of ions between them. The separator coating is a thin layer applied to the separator material to enhance its performance. This coating often includes materials that can improve the thermal stability and ion conductivity. The separator coating prevents short circuits between electrodes within the electrochemical cell and contributes to the overall safety and efficiency of the electrochemical cell.
The separator coating machinery in the electrochemical cell industry often utilizes the calendaring process, and electrochemical cell separators can be produced using either the "wet" or "dry" manufacturing processes.
In dry method, raw materials, typically polyethylene (PE) or polypropylene (PP), are mixed and melted. The molten polymer is then extruded through a T-shaped die, forming a continuous, flat sheet. The extruded sheet is subjected to rapid drawdown, which means it is stretched in both the machine direction (MD) and transverse direction (TD) of the sheet. This stretching helps achieve the desired thickness and properties of the separator. The stretched sheet is then subjected to a heat-setting process, where it is exposed to elevated temperatures. This heat treatment stabilizes the polymer structure and ensures the final separator's properties.
In wet production process for electrochemical cell separators, a polyolefin, like polyethylene (PE) or polypropylene (PP), is mixed with a hydrocarbon liquid (paraffin oil and methylene chloride are commonly used as the hydrocarbon liquid) or a low-molecular-weight diluent above its melting temperature. This creates a homogeneous mixture. The mixture is then extruded to form a casting film. This film is initially in a gel-like state. The casting film is stretched in both the machine direction (MD) and the transverse direction (TD). This biaxial stretching imparts the desired thickness and porosity to the separator. After stretching, the film goes through a solvent extraction process. A volatile solvent, like methylene chloride, is used to extract the hydrocarbon liquid from the film. This extraction process creates micro-pores in the separator. The resulting separator has a porous structure that allows the flow of ions while maintaining physical separation between the cell's electrodes. A polymer, often polyethylene (PE) or polypropylene (PP), is dissolved in a suitable solvent to create a polymer solution. This solution contains the polymer in a dissolved state. The polymer solution is then spread onto a substrate or support material, forming a wet film. As the solvent is evaporated or coagulated, the polymer starts to solidify and precipitate, resulting in the formation of a wet gel-like sheet. The wet gel sheet is passed through a solvent extraction process, where the remaining solvent is removed. This step helps create a porous structure within the separator as the solvent evaporates or is washed away. After solvent extraction, the wet separator is dried to remove any residual solvent completely. Then, the separator goes through a heat-setting process where it is exposed to elevated temperatures, which further stabilizes the polymer structure and ensures the final separator's properties.
However, these conventional methods are limited for the coating of two-dimensional electrode. Further, the conventional methods available for the separator coating on the three-dimensional electrode, utilizes ordinary spraying devices and the method to coat three-dimensional electrode poses significant challenges such as non-uniform coating of the separator material on the three-dimensional electrode which reduces the active surface area and reduces overall performance of the electrode, high spraying pressure of the spraying devices damages the fragile surface of the three-dimensional electrode, and also there is a wastage of significant amount of separator coating material while coating the three dimensional electrode which increase the overall cost of the process.
KR20140007752A, discloses a device and a method for coating a secondary battery separator. The device includes a coating part dipping a separator sheet in a coating solution and forming a coating layer on the surface of the separator sheet; a drying part performing a dry process on the coating layer formed on the surface of the separator sheet by using heat of a high temperature; a cutting part cutting the edge of the separator sheet with dried coating layer in a longitudinal direction; and a recoiler part recoiling the separator sheet with a cut edge. However, this invention fails to provide a method for applying the uniform separator coating on three-dimensional electrodes.
KR102553859B1, discloses a method for electrophoretic deposition of an electrode film on a three-dimensional substrate, comprising: (i) providing a dispersion comprising a solvent, wherein the dispersion comprises a charge agent and charged particles dispersed therein; (ii) applying an electrical current sufficient to deposit a film comprising particles on a surface area of a substrate, the particles comprising functionalized porous carbon, graphite, graphene, carbon nanoparticles, carbon nanotubes, carbon fibers and carbon rods, nanowires, fullerenes, silicon particles and lithium titer. A method comprising at least one LTO particle, wherein the ratio between the charged particle and the charging agent is from 1:10 %w/w to 10:1 %w/w. However, this invention fails to provide a method for applying the uniform separator coating on three-dimensional electrodes.
Therefore, there is need for a method for applying separator coating on three-dimensional electrode.

OBJECT OF THE INVENTION
The main object of the invention is to provide a method for applying separator coating on three-dimensional electrode.
Another object of the invention is to provide a method for applying separator coating on three-dimensional electrode that generates unidirectional flow of air through three-dimensional electrode for uniform coating and drying of separator coating material on three-dimensional electrode.
Yet another object of the invention is to provide a method for applying separator coating on three-dimensional electrode that works at optimal spraying pressure, conserving the structural integrity of the three-dimensional electrode.
Still another object of the invention is to provide a method for applying separator coating on three-dimensional electrode which is cost effective.

SUMMARY OF THE INVENTION
The present invention relates to provide relates to a method for applying separator coating on three-dimensional electrode.
In an embodiment, the present invention provides a method for applying separator coating on three-dimensional electrode comprises step of: a) connecting a vacuum pump to a vacuum base plate; b) placing a three-dimensional electrode to be coated on an electrode die of said vacuum base plate; c) establishing a seal area between said vacuum base plate and a closed vacuum chamber; d) securing a spraying apparatus on said closed vacuum chamber; e) connecting an air compressor to said spraying apparatus to generate and supply compressed air for coating; f) energizing said vacuum pump thereby creating a vacuum pressure to hold said three-dimensional electrode securely on said electrode die and to evacuate the air from said closed vacuum chamber; g) energizing said air compressor to apply ceramic separator coating on said three-dimensional electrode by a spray nozzle of said spraying apparatus; h) de-energizing said air compressor after spraying operation is complete; and i) de-energizing said vacuum pump to release said three-dimensional electrode from said electrode die after coating of ceramic separator is complete on said three-dimensional electrode.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings and detailed description of the invention appended herewith.

BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of a method for applying separator coating on three-dimensional electrode of the present invention may be obtained by reference to the following drawings:
Figure 1 is a flowchart of a method for applying separator coating on three-dimensional electrode according to an embodiment of the present invention.
Figure 2 is a block diagram of a method for applying separator coating on three-dimensional electrode according to an embodiment of the present invention.
Figure 3 is an isometric view of an arrangement of separator coating device on applying separator coating on three-dimensional according to an embodiment of the present invention.
Figure 4a is a cross-sectional view of an uncoated three-dimensional electrode according to an embodiment of the present invention.
Figure 4b is a cross-sectional view of a coated three-dimensional electrode according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The present invention relates to a method for applying separator coating on three-dimensional electrode.
In an embodiment, the present invention provides a method for applying separator coating on three-dimensional electrode comprises step of: a) connecting a vacuum pump to a vacuum base plate; b) placing a three-dimensional electrode to be coated on an electrode die of said vacuum base plate; c) establishing a seal area between said vacuum base plate and a closed vacuum chamber; d) securing a spraying apparatus on said closed vacuum chamber; e) connecting an air compressor to said spraying apparatus to generate and supply compressed air for coating; f) energizing said vacuum pump thereby creating a vacuum pressure to hold said three-dimensional electrode securely on said electrode die and to evacuate the air from said closed vacuum chamber; g) energizing said air compressor to apply ceramic separator coating on said three-dimensional electrode by a spray nozzle of said spraying apparatus; h) de-energizing said air compressor after spraying operation is complete; and i) de-energizing said vacuum pump to release said three-dimensional electrode from said electrode die after coating of ceramic separator is complete on said three-dimensional electrode.
Referring to Figure 1, a flowchart of a method for applying separator coating on three-dimensional electrode according to an embodiment of the present invention is depicted. The method for applying separator coating on a three-dimensional electrode comprising steps of: a) connecting a vacuum pump (3) to a vacuum base plate (1); b) placing a three-dimensional electrode (4) to be coated on an electrode die (2) of said vacuum base plate (1); c) establishing a seal area between said vacuum base plate (1) and a closed vacuum chamber (8); d) securing a spraying apparatus (6) on said closed vacuum chamber; e) connecting an air compressor (5) to said spraying apparatus (6) to generate and supply compressed air for coating; f) energizing said vacuum pump (3) thereby creating a vacuum pressure to hold said three-dimensional electrode (4) securely on said electrode die (2) and to evacuate the air from said closed vacuum chamber (8); g) energizing said air compressor (5) to apply ceramic separator coating on said three-dimensional electrode (4) by a spray nozzle (7) of said spraying apparatus (6); h) de-energizing said air compressor (5) after spraying operation is complete; and i) de-energizing said vacuum pump (3) to release said three-dimensional electrode (4) from said electrode die (2) after coating of ceramic separator is complete on said three-dimensional electrode (4).
The vacuum pump (3) is configured to provide unidirectional flow of air through said three-dimensional electrode (4) thereby forming a uniform coating on said three-dimensional electrode (4) and said vacuum pump (3) creates a vacuum pressure in the range of 0.02 bar to 0.1 bar.
The shape of said three-dimensional electrode (4) to be coated is of any hexagonal shape. The air compressor (5) creates an air pressure in the range of 0.1 bar to 4 bar. The diameter of orifice of said spray nozzle (7) is in the range of 0.1 mm to 2 mm and the standoff distance between said spray nozzle (7) and the three-dimensional electrode (4) is in the range of 2 cm to 50 cm.
The ceramic separator coating material is but not limited to a boron nitride (BN), aluminium oxide (Al2O3), and titanium dioxide (TiO2) suspension and the ceramic separator coating concentration is in the range of 5 to 30 w/v % of ceramic powder in solvent.
Referring to Figure 2, a block diagram of a method for applying separator coating on three-dimensional electrode according to an embodiment of the present invention is depicted. The method for applying separator coating on a three-dimensional electrode comprising steps of: a) connecting a vacuum pump (3) to a vacuum base plate (1); b) placing a three-dimensional electrode (4) to be coated on an electrode die (2) of said vacuum base plate (1); c) establishing a seal area between said vacuum base plate (1) and a closed vacuum chamber (8); d) securing a spraying apparatus (6) on said closed vacuum chamber (8); e) connecting an air compressor (5) to said spraying apparatus (6) to generate and supply compressed air for coating; f) energizing said vacuum pump (3) thereby creating a vacuum pressure to hold said three-dimensional electrode (4) securely on said electrode die (2) and to evacuate the air from said closed vacuum chamber; g) energizing said air compressor (5) to apply ceramic separator coating on said three-dimensional electrode (4) by a spray nozzle (7) of said spraying apparatus (6); h) de-energizing said air compressor (5) after spraying operation is complete; and i) de-energizing said vacuum pump (3) to release said three-dimensional electrode (4) from said electrode die (2) after coating of ceramic separator is complete on said three-dimensional electrode (4).
Referring to Figure 3, an isometric view of an arrangement of separator coating device for applying separator coating on three-dimensional according to an embodiment of the present invention is depicted. The separator coating device comprises of a vacuum base plate (1), an electrode die (2), a vacuum pump (3), a three-dimensional electrode (4), an air compressor (5), a spraying apparatus (6) and a closed chamber (8). The vacuum pump (3) is connected to said vacuum base plate (1) to maintain the unidirectional flow of air through said three-dimensional electrode (4) and to create vacuum pressure to hold said three-dimensional electrode (4) securely on said electrode die (2). The vacuum pump (3) creates a vacuum pressure in the range of 0.02 bar to 0.1 bar.
An uncoated three-dimensional electrode (4) as shown in Figure 4(a) is placed on said electrode die (2) of said vacuum base plate (1) and seal area is established between said vacuum base plate (1) and said closed vacuum chamber (8) to prevent any leakage.
The spraying apparatus (6) is secured on said closed vacuum chamber (8) and connected to said air compressor (5) to generate and supply compressed air for coating. The ceramic suspension material that is to be coated on said three-dimensional electrode is filled in the container of said spraying apparatus (6).
The vacuum pump (3) creates a vacuum pressure to hold said three-dimensional electrode (4) securely on said electrode die (2) and evacuates the air from said closed vacuum chamber (8) which assist in maintaining the unidirectional flow of air through said three-dimensional electrode (4) which helps ceramic separator coating material to flow down on the surface and inner walls of the three-dimensional electrode and uniformly coating the three-dimensional electrode (4) as shown in Figure 4(b) with separator coating. The size of said vacuum base plate (1) is variable as per the size of said three-dimensional electrode (4).
The air compressor (5) is connected to said spraying apparatus (6) that helps ceramic solution to be sprayed as an aerosol which is the mixture of ceramic suspension and air to spray on said three-dimensional electrode (4) through said spraying apparatus (6). The air compressor (5) creates an optimal air pressure in the range of 0.1 bar to 4 bar preventing the damage of electrode structure.
The spraying apparatus (6) includes a spray nozzle (7) and the orifice diameter of said spray nozzle (7) is in range of 0.1 mm to 2 mm. The arrangement of nozzle includes but not limited one unit but also multiple units on the basis of top surface area of said three-dimensional electrode (4). For small top surface area of said three-dimensional electrode (4) of up to 30 mm circumscribed circle diameter can be covered with a single nozzle. Subsequently, the large surface area of said three-dimensional electrode (4) more than 30 mm circumscribed circle diameter is covered with a multiple nozzle. The ceramic suspension material is but not limited to boron nitride (BN), aluminium oxide (Al2O3), and titanium dioxide (TiO2) suspension. The ceramic suspension concentration is in range of 5 to 30 w/v % of ceramic powder in solvent. The standoff distance between said spray nozzle (7) of said spraying apparatus (6) and said three-dimensional electrode (4) is kept between 2 cm to 50 cm and said vacuum pump (3) and said air compressor (5) are simultaneously switched on to apply ceramic separator coating on said three-dimensional electrode (4).
Therefore, the present invention provides method for applying separator coating on three-dimensional electrode for uniform coating of separator coating material which reduces the cost and the wastage separator coating material and works at optimal pressure conserving the structural integrity of the three-dimensional electrode.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

,CLAIMS:CLAIMS

We claim:
1. A method for applying separator coating on three-dimensional electrode, comprising steps of:
a. connecting a vacuum pump (3) to a vacuum base plate (1);
b. placing a three-dimensional electrode (4) to be coated on an electrode die (2) of said vacuum base plate (1);
c. establishing a seal area between said vacuum base plate (1) and a closed vacuum chamber;
d. securing a spraying apparatus (6) on said closed vacuum chamber (8);
e. connecting an air compressor (5) to said spraying apparatus (6) to generate and supply compressed air for coating;
f. energizing said vacuum pump (3) thereby creating a vacuum pressure to hold said three-dimensional electrode (4) securely on said electrode die (2) and to evacuate the air from said closed vacuum chamber (8);
g. energizing said air compressor (5) to apply ceramic separator coating on said three-dimensional electrode (4) by a spray nozzle (7) of said spraying apparatus (6);
h. de-energizing said air compressor (5) after spraying operation is complete; and
i. de-energizing said vacuum pump (3) to release said three-dimensional electrode (4) from said electrode die (2) after coating of ceramic separator is complete on said three-dimensional electrode (4).

2. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein said vacuum pump (3) is configured to provide unidirectional flow of air through said three-dimensional electrode (4) thereby forming a uniform coating on said three-dimensional electrode (4).
3. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein said vacuum pump (3) creates a vacuum pressure in the range of 0.02 bar to 0.1 bar.
4. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein the shape of said three-dimensional electrode (4) is of any hexagonal shape.
5. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein said air compressor (5) creates an air pressure in the range of 0.1 bar to 4 bar.

6. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein an orifice diameter of said spray nozzle (7) is in the range of 0.1 mm to 2 mm.

7. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein said ceramic separator coating material is but not limited to a boron nitride (BN), aluminium oxide (Al2O3), and titanium dioxide (TiO2) suspension.

8. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein the ceramic separator coating concentration is in the range of 5 to 30 w/v % of ceramic powder in solvent.

9. The method for applying separator coating on three-dimensional electrode as claimed in claim 1, wherein the standoff distance between said spray nozzle (7) and the three-dimensional electrode (4) is in the range of 2 cm to 50 cm.