DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A PROCESS TO FABRICATE 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 field of three-dimensional electrode. More particularly, the present invention relates to a process to fabricate three-dimensional electrode having an array of blind holes.

BACKGROUND OF THE INVENTION
A two-dimensional electrode is a thin film of material that conducts electricity. It is typically used in electronic devices, such as batteries and super capacitors, to collect and transfer electrons.
The widely adopted process in manufacturing of thin-film electrodes is the slurry casting process. Electrodes in the slurry casting process are fabricated by coating a substrate with a mixture, or slurry, containing active materials, conductive additives, and a liquid binder. This mixture is then cast onto the substrate, forming a wet layer. Afterward, the solvent is evaporated, leaving a dry electrode film. The slurry casting process is commonly used in the production of thin-film electrodes for conventional Li-ion batteries.
The trade-off between energy and power density in a conventional two dimensional electrodes arises from the alignment of electron and ion transport along the thickness of the thin-film electrode. While thin electrodes enhance power density by facilitating quicker transport but increasing electrode thickness for higher energy density introduces a proportional dead mass, limiting the overall performance, which increases the volume of the electrode, and decreases power density. Further, surface cracks are developed at small strains in these thin-film electrodes under repeated bundling of thin-film electrodes, limiting the operational life of the battery.
KR101575540B1 discloses a coplanar secondary battery equipped with a barrier. More specifically, provided is a coplanar secondary battery equipped with a barrier, which comprises: a positive and a negative electrode provided on the same layer and separated to one another; a lower exterior material provided on the bottom of the positive and the negative electrode; and a barrier protruding from the lower exterior material toward a space within the positive and the negative electrode.
KR20050009245A discloses an anode material for a lithium ion secondary battery and its preparation process. An anode for a lithium ion secondary battery using the anode material, and a lithium ion secondary battery using the anode, to improve initial efficiency, cycle characteristics, high rate charge/discharge and load characteristics. The process comprises the step of pressurizing isotopically a spherical graphite. Preferably, the process comprises the steps of pressurizing isotopically a spherical graphite; molding the pressurized graphite; and disintegrating the molded body. Preferably, the spherical graphite is obtained by making a needle-like graphite into a spherical one. Preferably, the anode material has a ratio of peak intensity at face by X-ray diffraction, of 0.004 or more.
The drawbacks related to these conventional process are that these conventional process are limited for producing two dimensional electrode and also repeated cycling of thin-film electrodes causes the formation of surface cracks at small strains, which leads to production of defective electrode and also reduces the battery's lifespan.
Therefore, there is need for a process to fabricate three dimensional electrode without any cracks or defects in the microstructure by ensuring stress relaxation during the electrode fabrication process and also there is need of fabrication of three-dimensional that minimizes the distance for ions to travel in three-dimensional electrode, leading to improved power density.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a process to fabricate three-dimensional electrode having an array of blind holes.
Another object of the present invention is to provide a process to fabricate three-dimensional electrode without any cracks or defects in the microstructure by ensuring stress relaxation during the electrode fabrication process.
Yet another object of the present invention is to provide a process to fabricate three-dimensional electrode which minimizes the distance for ions to travel in three-dimensional electrode leading to improved power density.
Still another object of the present invention is to provide a process to fabricate three-dimensional electrode which is scalable and manufacturing process for making electrode.

SUMMARY OF THE INVENTION
The present invention relates to a process to fabricate three-dimensional electrode.
In an embodiment, the present invention provides a process to fabricate three-dimensional electrode comprising steps of: (a) placing an electrode material in a die; (b) pressing the electrode material with a flat press punch to achieve a flat pressed electrode; (c) coating the top surface of the flat pressed electrode with a dry lubricant thereby avoiding sticking of the electrode material to the die; (d) pressing a pin punch into the flat pressed electrode; (e) removing the pin punch from the flat pressed electrode to obtain the three-dimensional electrode having an array of blind holes.
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 process to fabricate three-dimensional electrode of the present invention may be obtained by reference to the following drawings:
Figure 1 is a flowchart of a process to fabricate three-dimensional electrode according to an embodiment of the present invention.
Figure 2 is a schematic view of a process to fabricate 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 process to fabricate three-dimensional electrode.
In an embodiment, the present invention provides a process to fabricate three-dimensional electrode comprising steps of: (a) placing an electrode material in a die; (b) pressing the electrode material with a flat press punch to achieve a flat pressed electrode; (c) coating the top surface of the flat pressed electrode with a dry lubricant thereby avoiding sticking of the electrode material to the die; (d) pressing a pin punch into the flat pressed electrode; (e) removing the pin punch from the flat pressed electrode to obtain the three-dimensional electrode having an array of blind holes.
Referring to Figure 1, a flowchart of a process to fabricate three-dimensional electrode according to an embodiment of the present invention is depicted. The process is implemented via a set of machine or hardware components. The process include a plurality of steps.
At step (a), the process comprises placing an electrode material in a die. The electrode material is a flexible and shapeable material. The die holds the electrode material in a stable position.
At step (b), the process comprises pressing the electrode material with a flat press punch for obtaining a flat pressed electrode. The flat press punch apply a uniform pressure on the electrode material.
At step (c), the process comprises coating a top surface of the flat pressed electrode with a dry lubricant, thereby avoiding sticking of the electrode material to the die. The dry lubricant is preferably graphite powder.
At step (d), the process comprises pressing a pin punch into the flat pressed electrode. The pin punch have an array of pins that creates the array of holes. each pin of the array of pins in the pin punch has a diameter ranging from 100-2000 micrometers and each pin of the array of pins is positioned in a pattern, maintaining an edge to edge distance range from 20 to 1500 microns between adjacent pins. Also, the step (d) of pressing the pin punch into the flat pressed electrode is carried out multiple times.
At step (e), the process comprises removing the pin punch from the flat pressed electrode to obtain a three-dimensional electrode having an array of holes.
The pressing step is carried out either in a single step, or in multiple steps. For multistep pressing, the pin punch is inserted such that the pins penetrate the electrode up to 50% of the desired depth of the hole at a time, followed by extraction up to 49% of the desired depth of the hole at a time, out of electrode.
The removing step of the pin punch is carried out either in a single step, or in multiple steps. For multistep removal, the pin punch is removed such that the pins are extracted from the electrode up to 50% of the desired depth of the hole at a time, followed by re-insertion up to 49% of the desired depth of the hole at a time, back into the electrode. After every motion of the pin punch, the pin punch is held in place for stress relaxation. This process is repeated until the required depth of the hole is achieved to form a three dimensional electrode that include an array of holes with a diameter ranging between 100-2000 micrometers and a wall thickness of holes in range from 20-1500 microns.
Referring Figure 2 is a schematic view of a process to fabricate three-dimensional electrode according to an embodiment of the present invention is depicted. The electrode material placed in the die is pressed with a flat press against a base plate to obtain a flat pressed electrode. The top surface of the flat pressed electrode so obtained is coated with a dry lubricant. Now, a pin punch having array of pins is pressed into the coated flat pressed electrode. The pin punch is held into the flat pressed electrode and then pin punch is limitedly released from the electrode material and then again it is pressed into the electrode material. This process is repeated until the required depth of the hole is achieved and then the pin punch is finally released from the flat pressed electrode to obtain the three-dimensional electrode.

EXAMPLE 1
Analysis of reduction of ion travel distance
The present invention provides a process to fabricate three-dimensional electrode without any cracks or defects in the microstructure by ensuring stress relaxation during the electrode fabrication process and also provides fabrication of three-dimensional that minimizes the distance for ions to travel in three-dimensional electrode, leading to improved power density.
Further, the Nernst equation relates the electrode potential to the concentration gradient of lithium ions, while Fick’s law describes diffusion as a flux proportional to the concentration gradient, modified to account for tortuosity and charge. Also, if cylindrical electrode model is used, with inner and outer radii influencing ion flux and current. For 2D electrodes, concentration gradients are higher compared to 3D honeycomb architectures, which reduce these gradients and improve ion transport.

EXAMPLE 2
Analysis of improvement in power density
The energy density of a cell is given by (refer to Equation (1)):
-Equation (1)
where, ?????? is the specific capacity (Ah/g), and ?? is the voltage (volt).
The power density of a cell is given by (refer to Equation (2)):
- Equation (2)
where, ?? is the time taken for a cycle.
When the cell is charged at a higher C rate, the achievable capacity is limited due to the kinetics in the system. Based on the structure of the present invention, the electronic resistance is lower than that of current lithium-ion batteries. Also, due to the linear ion diffusion channels and the tortuosity of the present invention, the ions take a shorter pathway. This enhances both the ionic diffusion and electronic conduction, the synergy of which results in a much faster charging. This imparts higher power density for the present invention. This dimensional advantage gives a minimum of twice improvement in the power density compared to the present market values. If all the conditions are right, an improvement of 4X is achieved.
Therefore, the present invention provides a process to fabricate three-dimensional electrode without any cracks or defects in the microstructure by ensuring stress relaxation during the electrode fabrication process and also provides fabrication of three-dimensional that minimizes the distance for ions to travel in three-dimensional electrode, leading to improved power density.
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 principle 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 process to fabricate three-dimensional electrode comprising the steps of:
a) placing an electrode material in a die;
b) pressing the electrode material with a flat press punch for obtaining a flat pressed electrode;
c) coating a top surface of the flat pressed electrode with a dry lubricant, thereby avoiding sticking of the electrode material to the die;
d) pressing a pin punch into the flat pressed electrode; and
e) removing the pin punch from the flat pressed electrode to obtain a three-dimensional electrode having an array of holes.
2. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said electrode material is a flexible and shapeable material.
3. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said die holds the electrode material in a stable position.
4. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said flat press punch apply a uniform pressure on the electrode material.
5. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said electrode material is pressed via the flat press punch with a flat press load in range from 50N to 5000N.
6. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said dry lubricant is preferably graphite powder.
7. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said pin punch have an array of pins that creates the array of holes.
8. The process to fabricate three-dimensional electrode as claimed in claim 7, wherein each pin of the array of pins in the pin punch has a diameter ranging from 100-2000 micrometers and each pin of the array of pins is positioned in a pattern, maintaining an edge to edge distance range from 20 to 1500 microns between adjacent pins.
9. The process to fabricate three-dimensional electrode as claimed in claim 1, wherein said step (d) of pressing the pin punch into the flat pressed electrode is carried out multiple times.