An electrode, a jelly roll and processes thereof

Abstract

The present disclosure provides an electrode (100) comprising: a) an insulation material (101); b) a current collector (102); and c) an active material layer (103); wherein the current collector has a first portion and a second portion; wherein the first portion has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector; and wherein the second portion has a coating of the active material layer (103) on top side (103a) and bottom side (103b) of the current collector. The present disclosure also provides a process for preparation of the electrode, an electrochemical cell, a jelly roll, a battery, and use of the electrode (100).

Description

AN ELECTRODE, A JELLY ROLLAND PROCESSES THEREOFFIELD OF INVENTION

[0001] The present disclosure broadly relates to the field of battery. Particularly, the present disclosure relates to an electrode and the process of preparation of the electrode.BACKGROUND OF INVENTION

[0002] With the seemingly increasing demand for concise yet efficient electronic devices, the demand for development of lightweight and high-capacity secondary batteries has also sharply increased. Among such secondary batteries, lithium-ion battery (LIB) exhibits high energy density and operating voltage with highly appreciable cycle life characteristics, due to which it has been widely used as an energy source for various electronic devices.

[0003] Based on the shape of a battery case, a secondary battery may be termed as a cylindrical battery having an electrode assembly mounted in a cylindrical metal container, a prismatic battery having an electrode assembly mounted in a prismatic metal container, and a pouch-shaped battery having an electrode assembly mounted in a pouch-shaped case formed of an aluminum laminate sheet. The electrode assembly may be in the form of a jelly roll type electrode assembly, which is configured to have a structure comprising a cathode sheet, an electrolyte sheet, and an anode sheet that are wound in a state in which the electrolyte is disposed between the cathode sheet and the anode sheet. The cathode sheets and anode sheets have an exposed portion called tab region, which is at the end of the respective current collector as a current path.

[0004] In cylindrical 4680 cells, tab regions are being crushed or welded as a part of cell design. During tab crushing at the cathode side, the active material coated region also gets crushed along with the tab region and results in short circuit with the anode. Hence, there is a need for insulating the exposed portion of the current collector from a short circuit. However, this additional coating of insulation material adds up to the weight of the electrode and also to the total weight of the battery. The increase in weight of the battery further leads to decrease in energy density.SUMMARY OF THE INVENTION

[0005] In a first aspect of the present disclosure, there is provided an electrode (100) comprising: a. an insulation material (101); b. a current collector (102); and c. an active material layer (103); wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a coating of the active material layer (103) on top side (103a) and bottom side (103b) of the current collector.

[0006] In a second aspect of the present disclosure, there is provided a process for preparation of the electrode as disclosed herein, the process comprising: a. mixing a first binder, a ceramic material, and a solvent to obtain a slurry of insulation material; b. blending an active material, a conductive additive and a second binder to obtain a mixture of active material layer; and c. coating the slurry of insulation material alternatively on a first portion of top side (101a) and bottom side (101b) of a current collector and coating the mixture of active material layer on a second portion of top side (103 a) and bottom side (103b) of the current collector, to obtain an electrode.

[0007] In a third aspect of the present disclosure, there is provided an electrochemical cell comprising: the electrode (100) as disclosed herein; a counter electrode (200); and an electrolyte (300).

[0008] In a fourth aspect of the present disclosure, there is provided a jelly roll comprising:(a) an electrode (100) comprising: i. an insulation material (101); ii. a current collector (102); and iii. an active material layer (103);(b) a counter electrode (200); and(c) an electrolyte (300),wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a coating of the active material layer (103) on top side (103a) and bottom side (103b) of the current collector; and wherein the electrode (100), the counter electrode (200) and the electrolyte (300) are stacked and wound such that the electrolyte (300) is disposed between the electrode (100), and the counter electrode (200).

[0009] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0010] In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure wherein:

[0011] Figure 1 depicts the schematic representation of the electrode (100), in accordance with an embodiment of the present disclosure.

[0012] Figure 2 depicts the schematic representation of a jelly roll, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0013] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to beunderstood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features. Definitions

[0014] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0015] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0016] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”.

[0017] Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of elements or steps but not the exclusion of any other element or step or group of element or steps.

[0018] The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.

[0019] The term “w / w” means the percentage by weight, relative to the weight of the total composition, unless otherwise specified.

[0020] The term "at least one" is used to mean one or more and thus includes individual components as well as mixtures / combinations.

[0021] The term “insulation material” as used herein refers to the material applied on a current collector so as to prevent electrical contact between the tab regions of an electrode in an electrochemical cell in the form of a jelly roll. In an aspect of thepresent disclosure, the insulation material comprises a ceramic material selected from boehmite, silica, alumina, zirconium oxide, or combinations thereof; and a first binder selected from polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF), poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), polyamides, or combinations thereof. In other aspects of the present disclosure, the insulation material is applied in the tab regions of a current collector to prevent the short circuits resulting from contacting of tab regions of an electrode while tab crushing.

[0022] The term “tab region” denoted in the present disclosure as “first portion” refers to the portion of a current collector where the active material is not coated, and insulation material is coated in an alternative manner.

[0023] The term “second portion” refers to the portion of a current collector where the active material layer is coated upon.

[0024] The term “current collector” refers to the electric bridging component, which collects electrical current generated at the electrodes of electrochemical devices and connect with external circuits. For the purpose of the present disclosure, the current collector includes but not limited to aluminium foil, glossy aluminium foils, carbon or polymer pre-coated aluminium foil or combinations thereof.

[0025] The term “first binder” refers to the polymeric substance that provides mechanical integrity to the insulation material by holding the ceramic material particles together in the insulation material to obtain an electrode. In the present disclosure, first binder includes but not limited to polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF), poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), polyamides, or combinations thereof.

[0026] The term “second binder” refers to the polymeric substance that provides mechanical integrity to the active material when loaded on a current collector to obtain an electrode. In the present disclosure, second binder includes but not limited to polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyethylene oxide, fluoroethylene vinyl ether (FEVE), fluoroethylene polymer (FEP), or combinations thereof.

[0027] The term “electrode active material” refers to the active constituent of an electrode, which comprises the particles that undergo oxidation or reduction, resulting in reversible ion storage. Examples of electrode active material in the present disclosure includes but not limited to layered oxides, nickel manganese cobalt (NMC), nickel cobalt aluminium (NCA), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), or combinations thereof.

[0028] The term “conductive additive” refers to the additive component in an electrode, that provides an electronic movement channel. The amount of conductive additive content is appropriately optimised to obtain higher discharge capacity and better cycling performance. In an aspect of the present disclosure, the conductive additive is selected from carbon black, graphene, mesoporous carbon, acetylene black, activated carbon, super P, carbon nanofiber, vapour grown carbon nanofiber, carbon nanotube, or combinations thereof.

[0029] The term “alternate coating” refers to coating of a material which occurs at irregular intervals on a surface. In an aspect of the present disclosure, there is provided an electrode (100) wherein the first portion of the current collector in the electrode has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector.

[0030] The term “progressively increasing” refers to the gradual increase in a parameter with respect to distance (length), position, or time. In an aspect of the present disclosure, first portion of a current collector has an alternate coating of the insulation material, wherein length of the alternating coating is progressively increasing from one end (102a) to another end (102b) of the current collector (102). The end of the cathode labelled as 102a was towards the inside of the roll and the end of the cathode labelled as 102b towards the outside of the roll. In other aspects of the present disclosure, the length of the alternate coating is progressively increasing as a function of thickness of the jelly roll sheet, the number of turns in a jelly roll electrochemical cell, and the circumference of each turn of the jelly roll electrochemical cell. The progressively increasing length of the alternate coating of insulation material is in a progression of x, x+ai, x+a2, > , x+an, wherein the values of ai, a2, .....and anare designed as a function of thickness of the activematerial layer affecting the number of turns and thereby the circumference of each turn.

[0031] The term “jelly roll” refers to an electrochemical cell setup wherein sheets of an electrode, a counter electrode and an electrolyte are stacked such that the electrolyte is disposed in between the electrode and the counter electrode and wound. The alternate coating of insulation material in a jelly roll comes in between each of the turns of first portions of current collector, where the side on which the insulation material is coated alternates in adjacent turns. In an aspect of the present disclosure there is provided a jelly roll having n number of turns and n is in a range of 30 to 60, wherein the first (innermost) turn having a circumference x is coated with insulation material with a length of ~x on top side. Further, the second turn having a circumference of x+ai is coated with insulation material having a length of ~x+ai on bottom side of the current collector. Furthermore, at the n+lthturn having a circumference of x+anis coated with insulation material having a length of ~x+anon bottom side of the current collector.

[0032] Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, weight in the range of 95% to 98% should be interpreted to include not only the explicitly recited limits of 95% to 98% but also to include sub-ranges, such as 95% to 97%, 96% to 97% and so forth, as well as individual amounts, including fractional amounts, within the specified ranges, such as 95.8%, 96.5%, and 97.55%.

[0033] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0034] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products, compositions, formulations, and methods are clearly within the scope of the disclosure, as described herein.

[0035] As discussed in the background, there is a need in the art to develop a technique to incorporate insulation material in the tab regions of a current collector in a jelly roll electrochemical cell without increasing the weight of the battery and also affecting mechanical integrity of the electrode. Further, the present disclosure aims to obtain an electrode comprising an insulation material alternately coated on a first portion of a current collector and an active material coated uniformly on a second portion of the current collector on top side and bottom sides. The present disclosure provides a solution to reduce the weight contributed by the insulation material by coating the same intermittently or alternatively in top side and bottom side of a current collector with progressively increasing lengths.

[0036] Accordingly, the present disclosure provides an electrode (100) comprising: a. an insulation material (101); b. a current collector (102); and c. an active material layer (103); wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a uniform coating of the active material layer (103) on top side (103 a) and bottom side (103b) of the current collector.

[0037] In an embodiment of the present disclosure, there is provided an electrode (100) comprising: a. an insulation material (101); b. a current collector (102); and c. an active material layer (103); wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating ofthe insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a coating of the active material layer (103) on top side (103 a) and bottom side (103b) of the current collector.

[0038] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the first portion and the second portion of both the top side and bottom side of the current collector (102) are separated by a distance in a range of 0 to 1 mm.

[0039] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the alternate coating of the insulation material has a thickness in a range of 0.002 to 0.006 cm; the alternate coating of the insulation material has a length in a range of 30 to 140 mm; the alternate coating of the insulation material has a width in a range of 0.2 to 0.5 cm; and volume of the insulation material is in a range of 0.1 to 0.4 cm3. In another embodiment of the present disclosure, the alternate coating of the insulation material has a thickness in a range of 0.003 to 0.005 cm; the alternate coating of the insulation material has a length in a range of 30 to 140 mm; the alternate coating of the insulation material has a width in a range of 0.25 to 0.4 cm; and volume of the insulation material is in a range of 0.2 to 0.3 cm3.

[0040] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the insulation material comprises a ceramic material selected from boehmite, silica, alumina, zirconium oxide, or combinations thereof; and a first binder is selected from polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF), poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), polyamides, or combinations thereof. In another embodiment of the present disclosure, the ceramic material is boehmite, and the first binder is polyvinylidene fluoride (PVDF).

[0041] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the ceramic material is in a weight range of 10 to 40% with respect to the total weight of the insulation material. In another embodiment of the present disclosure, the ceramic material is in a weight range of 15 to 25%with respect to the total weight of the insulation material. In yet another embodiment of the present disclosure, the ceramic material is in a weight range of 20% with respect to the total weight of the insulation material.

[0042] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the first binder is in a weight range of 60 to 90% with respect to the total weight of the insulation material. In another embodiment of the present disclosure, the first binder is in a weight range of 70 to 85% with respect to the total weight of the insulation material. In yet another embodiment of the present disclosure, the first binder is in a weight range of 80% with respect to the total weight of the insulation material.

[0043] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the active material layer comprises an electrode active material selected from layered oxides, nickel manganese cobalt (NMC), nickel cobalt aluminium (NCA), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), or combinations thereof; a conductive additive selected from carbon black, graphene, mesoporous carbon, acetylene black, activated carbon, super P, carbon nanofiber, vapour grown carbon nanofiber, carbon nanotube, or combinations thereof; and a second binder selected from polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, fluoroethylene vinyl ether (FEVE), fluoroethylene polymer (FEP), or combinations thereof. In another embodiment of the present disclosure, the electrode active material is nickel manganese cobalt (NMC); the conductive additive is super P; and the second binder is selected from polytetrafluoroethylene, polyvinylidene fluoride, or combinations thereof. In yet another embodiment of the present disclosure, the second binder is polytetrafluoroethylene .

[0044] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the electrode active material is in a weight range of 95 to 98% with respect to the total weight of the active material layer. In another embodiment of the present disclosure, the electrode active material is in a weight range of 97 to 98% with respect to the total weight of the active material layer.

[0045] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the conductive additive is in a weight range of 1 to 4% with respect to the total weight of the active material layer. In another embodiment of the present disclosure, the conductive additive is in a weight range of 1 to 3% with respect to the total weight of the active material layer.

[0046] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the second binder is in a weight range of 0.1 to 3% with respect to the total weight of the active material layer. In another embodiment of the present disclosure, the second binder is in a weight range of 0.5 to 2.5% with respect to the total weight of the active material layer.

[0047] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the electrode has an energy density in a range of 257 to 258 Wh / kg.

[0048] In an embodiment of the present disclosure, there is provided an electrode as disclosed herein, wherein the electrode has an electrode active material loading in a range of 30 to 50 mg / cm2

[0049] In an embodiment of the present disclosure, there is provided a process for preparation of the electrode as disclosed herein, the process comprising: a. mixing a first binder, a ceramic material, and a solvent to obtain a slurry of insulation material; b. blending an active material, a conductive additive and a second binder to obtain a mixture of active material layer; and c. coating the slurry of insulation material alternatively on a first portion of top side (101a) and bottom side (101b) of a current collector and coating the mixture of active material layer on a second portion of top side (103 a) and bottom side (103b) of the current collector, to obtain an electrode.

[0050] In an embodiment of the present disclosure, there is provided a process for preparation of the electrode as disclosed herein, the process comprising: a. mixing a first binder, a ceramic material, and a solvent to obtain a slurry of insulation material; b. blending an active material, a conductive additive and a second binder to obtain a mixture of active material layer; and c. coating the slurry of insulation material alternatively on a first portion of top side (101a) and bottom side (101b) ofa current collector and coating the mixture of active material layer uniformly / continuously on a second portion of top side (103a) and bottom side (103b) of the current collector, to obtain an electrode.

[0051] In an embodiment of the present disclosure, there is provided a process for preparation of the electrode as disclosed herein, wherein the slurry of insulation material has a viscosity in a range of 3000 to 4000 cP at 50 s.

[0052] In an embodiment of the present disclosure, there is provided a process as disclosed herein, wherein the solvent is selected from N-methyl pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), propylene carbonate (PC), or combinations thereof; and the solvent is in a weight range of 60 to 90% with respect to the total weight of the slurry of insulation material. In another embodiment of the present disclosure, the solvent is N-methyl pyrrolidone (NMP) and the solvent is in a weight range of 70 to 80% with respect to the total weight of the slurry of insulation material. In another embodiment of the present disclosure, the solvent is N-methyl pyrrolidone (NMP) and the solvent is in a weight range of 90 to 99% with respect to the total weight of the ceramic material.

[0053] In an embodiment of the present disclosure, there is provided a process as disclosed herein, wherein the slurry of insulation material comprises the ceramic material in a weight range of 17 to 20%, with respect to the total weight of the mixture of insulation material.

[0054] In an embodiment of the present disclosure, there is provided a process as disclosed herein, wherein the ceramic material has an average particle size in a range of 0.4 to 2 micron.

[0055] In an embodiment of the present disclosure, there is provided a process as disclosed herein, wherein the ceramic material and the first binder are in a weight ratio range of 2: 1 to 5: 1.

[0056] In an embodiment of the present disclosure, there is provided an electrochemical cell comprising: a. the electrode (100) as disclosed herein; b. a counter electrode (200); and an electrolyte (300).

[0057] In an embodiment of the present disclosure, there is provided a jelly roll comprising: a. the electrode (100) as disclosed herein; b. a counter electrode (200); and c. an electrolyte (300), wherein the electrode (100), the counter electrode (200) and the electrolyte (300) are stacked and wound such that the electrolyte (300) is disposed between the electrode (100), and the counter electrode (200); and wherein electrode tabs are connected to first portions of the electrode (100).

[0058] In an embodiment of the present disclosure , there is provided a jelly roll comprising: a. an electrode (100) having an insulation material (101), a current collector (102), and an active material layer (103); b. a counter electrode (200); and c. an electrolyte (300), wherein the electrode (100), the counter electrode (200) and the electrolyte (300) are stacked and wound such that the electrolyte (300) is disposed between the electrode (100), and the counter electrode (200); and wherein electrode tabs are connected to first portions of the electrode (100).

[0059] In an embodiment of the present disclosure, there is provided a jelly roll as disclosed herein, wherein the electrolyte is LiPFe salt dissolved in carbonate based solvents selected ethylene carbonate, dimethyl carbonate, vinyl carbonate or combinations thereof.

[0060] In an embodiment of the present disclosure, there is provided a battery comprising the electrochemical cell as disclosed herein.

[0061] Use of the electrode as disclosed herein, for manufacture of an electrochemical cell or a jelly roll.EXAMPLES

[0062] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices, and materials are described herein. It is to beunderstood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.Materials and Methods

[0063] The various chemicals and solvents used in the present disclosure are as follows:

[0064] Boehmite, A10(0H) having a particle size D50 of 0.1-1.2 pm, specific surface area of 8.0 - 8.3 m2 / g, loss on Ignition (LOI) of 17.2 - 17.4%, and conductivity of 39 - 42 pS / cm.

[0065] Poly vinylidene fluoride (PVDF; first binder)

[0066] N-methyl pyrrolidone (NMP; solvent)

[0067] Nickel manganese cobalt (NMC; active material)

[0068] Super P (conductive additive)

[0069] Polytetrafluoroethylene (PTFE; second binder)

[0070] Aluminium current collectorEXAMPLE 1Preparation of electrodes

[0071] An insulation material was prepared by mixing 3% of poly vinylidene fluoride (PVDF; first binder) in 97% by weight of N-methyl pyrrolidone (NMP) solvent to obtain a binder solution having a solid content of 6.5 ± 0.5 and a viscosity of 2000 ± 500 cP. 80% by weight of the binder solution and 20 % by weight of boehmite with respect to the total weight of the binder solution (ceramic material having average particle size of about 0.5 to 2), were mixed to obtain a slurry of insulation material having a solid content of 18 ± 0.5% and a viscosity of 3500 ± 500cP.

[0072] In another container, about 97.5% by weight of nickel manganese cobalt (NMC; electrode active material), 1.5% by weight of super P (conductive additive), and 1% by weight of polytetrafluoroethylene (PTFE; second binder) were blended to obtain a mixture of active material layer.

[0073] The mixture of the active material layer was uniformly coated by slot die coating on second portions (103a and 103b) of top side and bottom side of an aluminium current collector (102), About 0.7272g of the slurry of insulation material was coated alternatively by slot die coating on first portions (tab region; 101a) of top side and about 0.7272g of the slurry of insulation material was coated alternatively on first portion (tab region; 101b) of bottom side of the current collector (102) by slot die coating, with first and second portion within a distance of 0 to 1 mm apart, followed by drying to obtain a cathode electrode A. The alternate coating was carried out with each strip of the insulation material having a length progressively increasing from one end (102a) to another end (102b) of the current collector (102). The insulation material was coated with a thickness of 0.004cm and in a width of 0.3cm on each of the top side and the bottom side of the first portions of the current collector. The length of the strips was in a progression of x, x+ai, x+a2, , x+an, wherein the values of ai, a2, .....and anwere calculated and fixed to be a function of circumference of each turn in the roll, which is specifically provided in the table 1. The total weight of the insulation material (on top side and bottom side of the current collector) was about 1.4544g and the volume was 0.24 cm3. Figure 1 depicts the schematic representation of the electrode (100) where the length of each strip of alternate coating is progressively increasing from one end to another end. An alternate coating of insulation material having total length of 200 cm was coated on the first portions of the top side and bottom side of the current collector.EXAMPLE 2

[0074] Similarly, for comparative purposes, a cathode electrode B was fabricated by coating the mixture of active material layer uniformly on a second portions (103a and 103b) of top side and bottom side of an aluminium current collector (102). About 1.4544g of the slurry of insulation material was uniformly coated by slot die coating / nozzle on first portion (tab region; 101a) of top side and about 1.4544g of the same slurry was uniformly coated on first portion (tab region; 101b) of bottom side of the current collector (102), with first and second portions having a distanceof 0 to 1 mm apart, followed by drying to obtain a cathode electrode B. The insulation material was coated with a thickness of 0.004cm and in a width of 0.3cm. The total weight of the insulation material (on top side and bottom side of the current collector) was about 2.585g and a volume of 0.42672 cm3. A uniform coating of insulation material having length of 355.6 cm was coated on the first portions of the top side and bottom side of the current collector.

[0075] The electrodes A and B were separately roll pressed in the form of a film on top of the current collector in a two or multiple roller system, at a required pressure. The rollers were heated to h ve better compaction and solvent removal.EXAMPLE 3Preparation of a jelly roll cell

[0076] A jelly roll A (cylindrical 4680 cell) was prepared using the cathode electrode A by stacking the cathode electrode A, an electrolyte sheet comprising LiPFe lithium salt dispersed in carbonate-based electrolyte and an anode sheet (counter electrode) comprising synthetic and natural graphite, a binder and conductive carbon materials coated on a copper current collector such that the electrolyte was disposed between the cathode and anode. The anode sheet was rolled alone for the first 4 pre-turns in the jelly roll. Following the 4thturn of anode, the stacked sheets of anode, cathode electrode A and electrolyte were wound for about 50 turns. The end of the cathode labelled as 102a was towards the inside of the roll and the end of the cathode labelled as 102b towards the outside of the roll. The first turn of jelly roll (after the 4 turns of anode) had a circumference of 32.66 mm, in view of which the insulation material was coated with a length of x= 33mm. Figure 2 depicts the schematic representation for jelly roll A.

[0077] The below table 1 provides the coating length for each turn which is approximately equal to the circumference of the nLhturn of the jelly roll A.Table 1

[0078] As provided above, the length of alternate coatings on top side and bottom side was calculated and fixed in a progressively increasing manner from the inner turns of jelly roll towards the outer turns of the jelly roll.

[0079] Similarly, a jelly roll B (cylindrical 4680 cell) was prepared with electrodeB, electrolyte LiPFe lithium salt in carbonate-based electrolyte and anode of synthetic and / or natural graphite, binder and conductive carbon materials coated on a copper current collector.Comparative analysis of the electrodes A and B

[0080] The electrodes A and B were characterized for the energy density, wherein the energy density as calculated as described below.Energy density of a cell= total energy of cell / weight of the cell Total energy of the cylindrical 4680 cell= 96W / hWeight of the cell comprising electrode A= 373gm Energy density of the cell comprising electrode A = 96 / 373= 0.2573Wh / gm= 257.3Wh / Kg.Weight of the cell comprising electrode B= 374gmEnergy density of the cell comprising electrode B = 96 / 374= 0.2566Wh / gm= 256.6Wh / Kg.

[0081] The energy density of the electrode A with alternate coating of insulation material was found to be 257.3 Wh / kg. However, the electrode B with uniform coating of the insulation material exhibited an electrode density of 256.6 Wh / kg.

[0082] Therefore, the electrode A having alternate coating of insulation material reduced the overall weight of the electrode and thereby enhanced the energy density of the electrode. Furthermore, the advantages of economic benefit and source utilization was also attributed when the electrode of the present disclosure is used.ADVANTAGES OF THE PRESENT DISCLOSURE

[0083] The present disclosure provides an electrode comprising an insulation material coated alternatively on a first portion of top and bottom sides of a current collector. Minor weight reduction in the insulation material results in a major energy density change without affecting the safety of the cell. The insulation material coating on the first portion of current collector alternates the sides on adjacent turns of a jelly roll. In view of this, the length of the alternate coatings of insulation material is thereby arranged in a progressively increasing manner from one end to the other of the current collector. The disclosed electrode exhibits a decrease in dead weight of the cell from 2.59gm to 1.45gm, further reflecting in the increment in energy density from 256.6 Wh / kg to 257.3 Wh / kg. The electrode of the present disclosure hence provides an economic and convenient technique to achieve an electrode with enhanced energy density with safety standards.

Claims

I / We Claim:

1. An electrode (100) comprising: a. an insulation material (101); b. a current collector (102); and c . an active material lay er ( 103 ) ; wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a coating of the active material layer (103) on top side (103 a) and bottom side (103b) of the current collector.

2. The electrode as claimed in claim 1, wherein the first portion and the second portion of both the top side and bottom side of the current collector (102) are separated by a distance in a range of 0 to 1 mm.

3. The electrode as claimed in claim 1, wherein the alternate coating of the insulation material has a thickness in a range of 0.002 to 0.006 cm; the alternate coating of the insulation material has a length in a range of 30 to 140 mm; the alternate coating of the insulation material has a width in a range of 0.2 to 0.5 cm; and volume of the insulation material is in a range of 0.1 to 0.4 cm3.

4. The electrode as claimed in claim 1, wherein the insulation material comprises a ceramic material selected from boehmite, silica, alumina, zirconium oxide, or combinations thereof; and a first binder selected from polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF), poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), polyamides, or combinations thereof.

5. The electrode as claimed in claim 4, wherein the ceramic material is in a weight range of 10 to 40% with respect to the total weight of the insulation material.

6. The electrode as claimed in claim 4, wherein the first binder is in a weight range of 60 to 90%, with respect to the total weight of the insulation material.

7. The electrode as claimed in claim 1, wherein the active material layer comprises an electrode active material selected from layered oxides, nickel manganese cobalt (NMC), nickel cobalt aluminium (NCA), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), or combinations thereof; a conductive additive selected from carbon black, graphene, mesoporous carbon, acetylene black, activated carbon, super P, carbon nanofiber, vapour grown carbon nanofiber, carbon nanotube, or combinations thereof; and a second binder selected from polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, fluoroethylene vinyl ether (FEVE), fluoroethylene polymer (FEP), or combinations thereof.

8. The electrode as claimed in claim 7, wherein the electrode active material is in a weight range of 95 to 98%; the conductive additive is in a weight range of 1 to 4%; and the second binder is in a weight range of 0.1 to 3%, with respect to the total weight of the active material layer.

9. The electrode as claimed in claim 1, wherein the electrode has an energy density in a range of 257 to 258 Wh / kg.

10. The electrode as claimed in claim 1, wherein the electrode has an electrode active material loading in a range of 30 to 50 mg / cm211. A process for preparation of the electrode as claimed in claim 1, the process comprising: a. mixing a first binder, a ceramic material, and a solvent to obtain a slurry of insulation material; b. blending an active material, a conductive additive and a second binder to obtain a mixture of active material layer; andc. coating the slurry of insulation material alternatively on a first portion of top side (101a) and bottom side (101b) of a current collector and coating the mixture of active material layer on a second portion of top side (103a) and bottom side (103b) of the current collector, to obtain an electrode.

12. The process as claimed in claim 11, wherein the slurry of insulation material has a viscosity in a range of 2000 to 4000 cP at 50 s.

13. The process as claimed in claim 11, wherein the solvent is selected from N- methyl pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), propylene carbonate (PC), or combinations thereof; and the solvent is in a weight range of 60 to 90% with respect to the total weight of the slurry of insulation material.

14. The process as claimed in claim 11, wherein the slurry of insulation material comprises the ceramic material in a weight range of 17 to 20%, with respect to the total weight of the mixture of insulation material.

15. The process as claimed in claim 11, wherein the ceramic material has an average particle size in a range of 0.4 to 2 micron.

16. The process as claimed in claim 11, wherein the ceramic material and the first binder are in a weight ratio range of 2: 1 to 5: 1.

17. An electrochemical cell comprising: a. the electrode (100) as claimed in claim 1; b. a counter electrode (200); and c. an electrolyte (300).

18. A jelly roll comprising: a. an electrode (100) comprising: i. an insulation material (101); ii. a current collector (102); and iii. an active material layer (103); b. a counter electrode (200); and c. an electrolyte (300);wherein the current collector has a first portion and a second portion; wherein the first portion of the current collector has an alternate coating of the insulation material (101) on top side (101a) and bottom side (101b) of the current collector; wherein length of each of the alternate coating of the insulation material is progressively increasing from one end (102a) to another end (102b) of the current collector (102); and wherein the second portion of the current collector has a coating of the active material layer (103) on top side (103 a) and bottom side (103b) of the current collector; and wherein the electrode (100), the counter electrode (200) and the electrolyte (300) are stacked and wound such that the electrolyte (300) is disposed between the electrode (100), and the counter electrode (200).

19. A battery comprising the electrochemical cell as claimed in claim 17 or the jelly roll as claimed in claim 18.

20. Use of the electrode (100) as claimed in claim 1, for manufacture of an electrochemical cell in the form of a jelly roll.

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