Calendering roller for electrode formation and its manufacturing process

Abstract

Calendering roller for electrode formation and its manufacturing method. The invention relates to a calendering roller (10) for forming an electrode, characterized in that it comprises: a main roller body (11) made of composite material, cylindrical in shape, extending along a longitudinal reference axis (X); a layer of metallic material(s) (14) enveloping an external surface of said main body (11); a roller drive shaft (12) integral with the main body (11) and coaxial with respect to the longitudinal reference axis (X), said roller drive shaft (12) being capable of rotating the main body (11) around the central axis of the main roller body (11); and an induction heating means (15) having at least one working head connected to the main body (11) and extending at least partially around the central axis of the main body (11). Figure for the abstract: Figure 1

Description

Title of the invention: Calendering roller for forming an electrode and its manufacturing process

[0001] The present invention relates to a calendering roller that can be used in any kind of industry such as the paper industry or the automotive industry.

[0002] For this purpose, the invention relates more particularly to a calendering roller for the formation of an electrode for an electric battery cell, a device for manufacturing an electrode comprising a calendering roller and a method for manufacturing such a calendering roller.

[0003] The invention applies both to electrodes formed by dry method, i.e. without the use of solvent, and by wet method, i.e. with the use of a solvent.

[0004] The formation of an electrode by dry or wet process includes, in particular, at least one step of calendering an active electrode material between at least two cylindrical rollers. One of the final steps in the formation of a dry electrode is the rolling of the calendered active material onto a support, generally an aluminum or copper sheet.

[0005] In particular, prior art knows of a device for preparing an electrode comprising two calendering rollers between which the material to be calendered moves.

[0006] The prior art calendering rollers are made entirely of metallic material.

[0007] However, such rollers have rigidity problems, resulting in roller deformation during operation, which affects the dimensions and quality of the electrodes, for example a difference in thickness and / or porosity.

[0008] Furthermore, these rollers have a large diameter and are therefore cumbersome in electric battery cell production plants. In addition, these large dimensions necessitate modifications compared to smaller scales of development, particularly with regard to process development.

[0009] These large dimensions also have a negative impact on the contact pressure between the electrode material and the roller, thus increasing the risk of the electrode material becoming embedded in the external surface of the roller in contact with the material, but also the wear of the calendering rollers.

[0010] It is also known from the prior art to heat such a calendering roller by means such as a fluid passing through the roller or by electrical means with cartridges arranged inside such a roller.

[0011] However, these prior art methods for heating calendering rollers to form an electrode do not offer the required efficiency. Indeed, the metal roller is heated entirely, to the detriment of the roller surface in contact with the electrode material to be calendered.

[0012] The present invention aims to remedy the disadvantages of the prior art by proposing a calendering roller exhibiting better rigidity while efficiently heating the area intended to be in contact with the electrode material.

[0013] To this end, the invention relates to a calendering roller for forming an electrode, characterized in that it comprises: - a main roller body made of composite material, cylindrical in shape, extending along a longitudinal reference axis, - a layer of metallic material(s) enveloping an external surface of said main body, - a roller drive shaft integral with the main body and coaxial with respect to the longitudinal reference axis, said roller drive shaft being capable of rotating the main body around the central axis of the main roller body, and - an induction heating means linked to the main body and extending at least partially around the central axis of the main body.

[0014] According to one embodiment, the induction heating means is arranged coaxially with respect to the longitudinal reference axis, radially between the roller drive shaft and the metallic material layer.

[0015] According to one embodiment, the main roller body comprises a first inner layer of composite material, the induction heating means being disposed around the first inner layer of composite material, and a second layer of composite material disposed around the first inner layer and coaxially with said first inner layer, the induction heating means being disposed preferably between the first layer and the second layer, the metallic material layer enveloping an external surface of the second composite material layer of the main roller body.

[0016] According to one embodiment, the first layer of composite material comprises: - fibers such as carbon fibers, glass fibers, silica fibers, quartz fibers, polymer fibers, boron fibers, steel fibers, ceramic fibers, or aramid fibers and a resin such as an epoxy resin, a polyester resin, a phenolic resin, or a ceramic resin; the second layer of composite material comprises fibers such as carbon fibers, graphite fibers, or metallic fibers such as steel, stainless steel, titanium, or brass; and / or - a resin such as an epoxy resin, a polyester resin, a phenolic resin or a ceramic resin, and / or - the metallic material layer is made of steel.

[0017] According to one embodiment, the second layer of composite material of the main body has a thickness, taken radially with respect to the longitudinal reference axis, greater than a thickness taken radially with respect to the longitudinal reference axis of the first layer of composite material of the main body.

[0018] According to one embodiment, the induction heating means comprises a working head such as a coil embedded in a cylindrical solid substrate integral with the main roller body and configured to electrically isolate the coil from the first layer of composite material and the second layer of composite material, the heating means being configured so that the coil heats the metallic material layer and the second composite material layer when the coil is in an electromagnetically active operating state.

[0019] According to one embodiment, the substrate comprises, preferably is made of, a resin and / or the coil comprises copper and / or steel, preferably is made of copper or steel.

[0020] According to one embodiment, the metallic material layer comprises a chromium or tungsten carbide coating.

[0021] According to another aspect, the invention also relates to a device for preparing an electrode in which the device comprises at least one, preferably two, calendering rollers as described above.

[0022] The invention further relates to a method for manufacturing a calendering roller as described above, comprising at least the following steps: - formation of the main roller body equipped with the induction heating means and integral with the roller drive shaft, and - application of a layer of metallic material on the second layer of composite material.

[0023] According to one embodiment, the step of forming the main roller body equipped with the induction heating means and integral with the roller drive shaft comprises at least the following steps: - winding a mixture of fibers and resin around the roller drive shaft, forming a first layer of composite material bonded to the roller drive shaft, - arrangement of the induction heating means, preferably the working head comprising the coil embedded in a solid substrate, around the first layer of composite material, - winding a mixture of fibers and a [material] around the induction heating means, forming a second layer of composite material, and - application of a layer of metallic material on the second layer of composite material.

[0024] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which: - [Fig.1] [Fig.1] is a perspective view of a calendering roller according to one embodiment of the invention; - [Fig.2] [Fig.2] is a cross-sectional view of the calendering roller of [Fig.1] - [Fig. 3] [Fig. 3] is a partial enlarged view of a heating means for the calendering roller of the [Fig.2]; and - [Fig.4] [Fig.5] [Fig.6] [Fig.7] [Fig.8] Figures 4, 5, 6, 7 and 8 are views schematic, perspective, of steps in the manufacturing process of the calendering roller of [Fig.1], according to an embodiment of the invention; - [Fig.9] [Fig.9] is a partial side view of the preparation device of an electrode according to an embodiment of the invention.

[0025] For clarity, identical or similar elements are identified by identical reference signs throughout the figures.

[0026] Fig. 1 represents a calendering roller 10 for the formation of an active material film and an electrode according to an embodiment of the invention.

[0027] The calendering roller 10 comprises a main roller body 11. This main body 11 is cylindrical in shape extending along a longitudinal reference axis X and extends around a central axis parallel to the longitudinal direction X of elongation of the main body 11.

[0028] The main body of the roller 11 is made of composite material. Generally, the composite material comprises at least one reinforcement, preferably composed of fibers, embedded in at least one matrix such as a resin.

[0029] A roller drive shaft 12 passes through the central axis of the main roller body 11 in the longitudinal direction X. In other words, the main body locally and coaxially surrounds the drive shaft 12.

[0030] The roller drive shaft 12 can be made, preferably is made of composite material comprising reinforcements, for example, of carbon fibers, glass fibers, silica fibers, quartz fibers, polymer fibers, boron fibers, steel fibers, ceramic fibers and / or aramid fibers, the reinforcements being embedded in a matrix such as a resin, for example an epoxy resin, a polyester resin, a phenolic resin or a ceramic resin.

[0031] Preferably, the drive shaft is made of aramid fibers with an epoxy resin.

[0032] In an embodiment not shown, the roller drive shaft 12 has a hollow body.

[0033] The roller drive shaft 12 comprises two ends 13A and 13B comprising bearing rings to form bearings.

[0034] These bearing rings are made of metallic material.

[0035] A layer of metallic material 14 covers the main roller body 11 by surrounding it coaxially with respect to the reference axis X.

[0036] The metallic material layer 14 is steel and preferably hardened steel.

[0037] The metallic material layer 14 has a thickness greater than or equal to 1 mm, preferably greater than or equal to 3 mm and / or less than or equal to 30 mm, preferably less than or equal to 10 mm.

[0038] A coating is applied to the metallic material layer 14.

[0039] Preferably the coating is made of hard chrome or tungsten carbide.

[0040] A heating means 15 is arranged around the central axis of the main roller body 11 and extends in the longitudinal direction X.

[0041] More specifically, the heating means 15 is located inside the main roller body 11.

[0042] The heating means 15 is substantially cylindrical in shape.

[0043] The heating means 15 is an electromagnetic induction heating means.

[0044] The heating means has a thickness between 1% and 10% of the Total radial length of roller 10.

[0045] Fig. 2 shows the heating means 15 extending through the main roller body 11 in the longitudinal direction X and around the central axis of the main roller body 11.

[0046] With reference to figures 2 and 3, the main roller body 11 comprises a first layer of composite material 21 and a second layer of composite material 22.

[0047] The first layer of composite material 21 is located around the roller drive shaft 12 so as to locally wrap it.

[0048] The first layer of composite material 21 can be made with a reinforcement of carbon fibers, glass fibers, silica fibers, quartz fibers, polymer fibers, boron fibers, steel fibers, ceramic fibers or aramid fibers, with a matrix chosen from an epoxy resin, a polyester resin, a phenolic resin or a ceramic resin.

[0049] This first layer of composite material 21 is preferably composed of fibers with a high modulus of elasticity and little prone to being heated by induction, such as aramid with epoxy resin.

[0050] This first layer has a thickness between 5% and 80% of the total radial length of the roller.

[0051] The heating means 15 is arranged coaxially around the first layer of composite material 21.

[0052] In other words, the heating means 15 covers at least part of the first layer of composite material 21.

[0053] The second layer of composite material 22 is arranged coaxially around the heating means 15.

[0054] In other words, the second layer of composite material 22 covers the heating means 15.

[0055] This gives us a heating means 15 having the shape of a cylinder interposed radially between the first layer of composite material 21 and the second layer of composite material 22, these three layers being coaxial and joined in pairs.

[0056] The second layer of composite material 22 can be made with reinforcement of carbon fibers, graphite fibers, metallic fibers such as steel, stainless steel, titanium or brass, with a matrix chosen from a polyester resin, a phenolic resin or a ceramic resin.

[0057] This second layer of composite material 22 is preferably composed of fibers with a high elastic modulus and very inclined to be heated by induction, such as carbon with epoxy resin.

[0058] This layer has a thickness between 5% and 80% of the total radial length of the roller 10.

[0059] In a preferred embodiment of the invention, the second layer of composite material 22 has a greater thickness than the first layer of composite material 21. This difference in thickness between these two layers improves the rigidity of the calendering roller 10.

[0060] As shown in particular in [Fig.3], the heating means 15 includes a substrate 23 configured to ensure the transmission of mechanical stresses between the first layer of composite material 21 and the second layer of composite material 22 of the main roller body 11.

[0061] The substrate 23, preferably composed of an epoxy resin, corresponds to the thickness of the heating means 15.

[0062] A working head such as a coil 24 is embedded in the substrate 23 and disposed across the substrate 23 and is configured to heat the second layer of composite material 22 and the layer of metallic material 14. The heating means is thus connected by an electrical circuit, in particular by electrical wires connected to axially opposite ends of the working head, i.e. of the coil 24. The electrical circuit is in turn connected to an electrical power source.

[0063] The substrate 23 is also configured to electrically isolate the turns 25 of the coil 24. Portions of connecting wires of the coil 24 each pass through the material of the drive shaft 12 on axial portions along the longitudinal direction X on either side axially of the main roller body 11, then each extend radially, i.e. in an elevation direction Z, perpendicular to the longitudinal direction X before being connected to one end of the coil extending through the main roller body 11 along the longitudinal direction X and around the central axis of the main roller body 11. Preferably, at least portions of connecting wires to the coil 24 are formed by extensions of the turns of the coil 24.

[0064] This coil 24, associated with its helical shape, is preferably made of copper, and is configured so as to efficiently generate an electromagnetic field and to heat by electromagnetic induction the materials of the second layer of composite material 22 and of the layer of metallic material 14.

[0065] Depending on the mechanical constraints involved within the roller, this coil 24 can be made of more resistant materials such as steel.

[0066] A preferred manufacturing process for the calendering roller 10 will now be described with reference to Figures 4 to 8.

[0067] A first step consists of forming the main roller body 11 equipped with the induction heating means 15 and integral with the roller drive shaft 12.

[0068] Initially, one step consists of winding the reinforcement / matrix mixture, here composed of aramid fibers and epoxy resin, around a mandrel 26.

[0069] Preferably, the aramid fibers are oriented along the longitudinal direction X.

[0070] This winding is carried out by a well-known process commonly called the wet fiber winding method, as illustrated in [Fig. 4]. The resin is polymerized by the various processes known in the state of the art, for example by ambient temperature, an oven, or an autoclave.

[0071] Optionally, intermediate polymerizations and machining operations are carried out to obtain the desired quality in terms of polymerization and dimensions. Final machining of the outer casing is performed.

[0072] This first step makes it possible to obtain the roller drive shaft 12.

[0073] Preferably, the chuck 26 is removed once the roller drive shaft 12 is formed.

[0074] Thus, the drive shaft has a hollow body and thus allows the passage of the turns 25 of the coil 24 for its winding, as described in the third step of this process.

[0075] In another embodiment, the mandrel 26 is removed once the first layer of composite material 21 is formed, before the heating means 15 is realized.

[0076] Similarly, a second step consists of winding the associated reinforcement / matrix mixture, here composed of aramid fibers and epoxy resin, around the roller drive shaft 12, so as to form the first layer of composite material 21.

[0077] The aramid fibers and epoxy resin are wound around the roller drive shaft 12 until the thickness of the first layer of composite material 21 is between 5% and 80% of the radial length of the roller.

[0078] Preferably, the aramid fibers are oriented along the longitudinal direction X of roll body elongation 11.

[0079] This winding is also carried out by the wet fiber winding method.

[0080] The resin is also polymerized by various known prior art processes, for example by ambient temperature, in an oven, or in an autoclave. Optionally, intermediate polymerizations and machining operations are carried out to obtain the desired quality in terms of polymerization and dimensions.

[0081] An intermediate step consists of applying the two attached ends 13A and 13B around the drive shaft 12.

[0082] In order to be applied by shrink fitting, the two attached ends 13A and 13B are heated, inserted around axial end portions of the drive shaft 12, and cooled. The heating temperature during shrink fitting must be significantly higher than the operating temperature of the roller, in order to ensure that the attached ends 13A and 13B remain attached to the drive shaft 12 during the operation of the calendering roller 10.

[0083] This intermediate step can be carried out later, after the following steps which are described.

[0084] A third step consists of arranging the induction heating means 15 around the first layer of composite material 21. In [Fig. 6], only the coil 24 is shown. The coil 24 of the heating means 15 is embedded in the substrate 23, which is arranged by injection molding, so as to ensure the spacing between the turns 25 of the heating means 15 and the absence of voids between the turns 25 and the first layer of composite material 21. This substrate 23 is preferably the same epoxy resin as that of the first layer of composite material 21.

[0085] A mold can be used during this injection.

[0086] A fourth step consists of wrapping another associated reinforcement / matrix mixture, here composed of carbon fibers and epoxy resin, around the heating means 15 to form the second layer of composite material 22.

[0087] This winding is also carried out by the wet fiber winding method.

[0088] The resin is also polymerized by the various processes known in the state of the art, for example by ambient temperature, an oven or an autoclave.

[0089] Optionally, intermediate polymerizations and machining operations are carried out in order to obtain the desired quality in terms of polymerization and dimensions.

[0090] This fourth step makes it possible to obtain the second layer of composite material 22 of the main body of roller 11, as illustrated in [Fig.7].

[0091] Carbon fibers and epoxy resin are wound around the heating means 15 until a thickness of the second layer of composite material 22 is obtained that is between 5% and 80% of the total radial length of the roll.

[0092] Preferably, the carbon fibers are oriented along the longitudinal direction X of elongation of roller body 11.

[0093] Optionally, a final machining is carried out on the outer surface of the second layer of composite material 22.

[0094] The final step consists of applying the metallic material layer 14 around the second composite material layer 22, as illustrated in [Fig.8].

[0095] In order to be applied by shrink fitting, the metallic material layer 14 is heated, inserted around the second composite material layer 22, and cooled. The heating temperature during shrink fitting must be significantly higher than the operating temperature of the roller, in order to ensure that the metallic material layer 14 adheres to the second composite material layer 22 during roller operation.

[0096] Of course, the other possible materials, described previously, for the first layer of composite material 21, the second layer of composite material 22 and the roller drive shaft 12, are also applicable for this manufacturing process of the calendering roller 10.

[0097] Figure 9 represents part of a device 100 for preparing an electrode by dry route.

[0098] The device 100 as illustrated shows a plurality of calendering rollers 10 adjacent to each other and aligned along a transverse axis Y perpendicular to the longitudinal direction X.

[0099] In the embodiment illustrated in this figure, the device 100 is composed of six calendering rollers 10.

[0100] In another embodiment of the invention, the device 100 comprises at least one, preferably two calendering rollers 10.

[0101] An electrode material 30, here a powder of mixed active material, is present between two adjacent calendering rollers 10.

[0102] More specifically, the powder is present between a first calendering roller 10A and a second calendering roller 10B.

[0103] The powder takes the form of an electrode film by passing through the first set formed by the calendering roller 10A and the second calendering roller 10B and then through the second set formed by the calendering roller 10B and a third calendering roller 10C, and so on up to a sixth calendering roller 10F.

[0104] The fifth and sixth calendering rollers 10E and 10F of the device 100 also constitute lamination rollers of the electrode film on a support 40, for example copper or aluminum, forming an electrode.

[0105] In the following description, the operation of the calendering roller 10 according to the invention and the electrode preparation device 100 are detailed.

[0106] The manufacture of an electrode by dry process includes a first step of calendering an electrode material 30 by the device 100 between at least the first calendering roller 10A and the second calendering roller 10B, the calendering rollers 10 being set in rotary motion by the roller drive shaft 12.

[0107] The calendering rollers 10 can have different rotational speeds in order to shear the electrode material 30 by friction.

[0108] These calendering rollers 10 are heated by induction via the copper coil 24 through which an alternating electric current flows.

[0109] The coil 24 will rapidly and locally heat the second layer of composite material 22 made of carbon fibers and the metallic material layer 14 made of steel, these materials being inclined to be heated by induction, unlike aramid fibers.

[0110] The heat accumulated by the second layer of composite material 22 made of carbon fibers and the metallic material layer 14 made of steel will diffuse by conduction towards the electrode material 30, thus allowing it to be heated and to form an electrode film.

[0111] The aramid fiber materials with the epoxy resin of the first composite material layer 21 and the roller drive shaft 12 are not very prone to heating and are good thermal insulators. Therefore, the heat accumulated in the second composite material layer 22 and the metallic material layer 14 will preferentially diffuse towards the electrode material 30. The energy efficiency is close to 1, because the energy from the self-heating of the coil 24 during the passage of alternating current will diffuse equally and preferentially towards the second layer of composite material 22 made of carbon fibers and the metallic material layer 14 made of steel, these materials being good thermal conductors.

[0112] The advantage compared to the state of the art, i.e. heating a steel roller by fluid or cartridge, is that the amount of heat which is conducted and lost to the rotating guides of the roller, for example bearings or bushings, is significantly reduced, which makes it possible to significantly reduce the energy consumption of the equipment.

[0113] Such a calendering roller 10 with a main body 11 made of composite material has the advantage of having high rigidity while being lightweight.

[0114] This flexural rigidity is obtained in particular with materials with high modulus of elasticity located in the areas furthest from the center of the roll, namely the carbon fibers oriented along the longitudinal axis X of the second layer of composite material 22.

[0115] The mass of the calendering roller 10 and its rotational inertia are divided by four compared to a prior art steel calendering roller. Indeed, the density of the metal is 7.8 while that of the composite materials is approximately 1.7.

[0116] This allows for lower energy consumption to start and vary the angular speeds of the rollers.

[0117] This also makes it possible to greatly reduce the total mass of the calendering equipment, thus facilitating its transport and installation, its maintenance, and to significantly reduce the cost of the workshop slab which must support the mass of the calendering equipment.

[0118] Moreover, this achieved rigidity makes it possible to limit the diameter of the calendering rollers 10 for the same deflection under load compared to the state of the art, and thus significantly and additionally reduce the mass of the rollers.

[0119] This reduction in diameter also makes it easier to develop and scale up equipment; indeed, increases in roller widths during developments to move from laboratory scale to industrial production scale are generally accompanied by an increase in their diameter, in order to keep a reduced roller deflection.

[0120] However, changes in diameter generate undesirable effects and risks for the development of processes and equipment, including contact pressures and behaviors of the electrode material 30 which evolve in ways that are difficult to predict.

[0121] In addition, the prior art roll anti-flexing systems, such as jacks generating reverse flexing, are no longer necessary because the flexing and deflection of the calendering roll 10 according to the invention is divided by two compared to a prior art roll made of metallic material.

[0122] Indeed, the modulus of elasticity of steel is 200 GPa while that of the composite material with carbon fibers and epoxy resin is around 400 GPa in the longitudinal direction of the roller, considering carbon fibers oriented in the longitudinal direction of the roller, and this in the areas far from the center of the roller which contribute mainly to the quadratic moment of the roller, in other words the bending stiffness.

[0123] The thermal inertia of the calendering roller according to the invention is significantly reduced, the product of the density and the heat capacity of the metallic material is about 3,700 kJ.m-3.Kl and that of the composite material is 1,800 kJ.m-3.Kl.

[0124] Finally, the induction heating means 15 allows the outer metallic surface of the calendering roller 10, which is in contact with the electrode material 30, to be heated quickly and locally. The heat accumulated by the second layer of composite material made of the mixture of carbon fibers and epoxy resin and the metallic material 14 will be transmitted directly to the electrode material 30.

[0125] Indeed, the first layer of composite material 21 is made of a mixture of aramid fibers and epoxy resin and makes it difficult for the heat generated by the induction heating means 15 to diffuse, which allows the heat accumulated to remain at the level of the functional area which is the layer of metallic material 14 located on the outer surface of the calendering roller 10.

[0126] Thus, the materials used allow the roller to be heated very quickly but also to be cooled very quickly, because the accumulated energy is lower, resulting in reduced operating costs, reduced development costs and also a reduced environmental cost.

[0127] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

Claims

Demands

1. Calendering roller (10) for forming an electrode characterized in that it comprises: - a main roller body (11) of composite material, cylindrical in shape, extending along a longitudinal reference axis (X), - a layer of metallic material(s) (14) enveloping an external surface of said main body (11), - a roller drive shaft (12) integral with the main body (11) and coaxial with respect to the longitudinal reference axis (X), said roller drive shaft (12) being capable of rotating the main body (11) around the central axis of the main roller body (11), and - an induction heating means (15) connected to the main body (11) and extending at least partially around the central axis of the main body (11).

2. Calendering roller (10) according to claim 1, wherein the induction heating means (15) is arranged coaxially with respect to the longitudinal reference axis, radially between the roller drive shaft (12) and the metallic material layer (14).

3. Calendering roller (10) according to any one of claims 1 or 2, wherein the main roller body (11) comprises a first inner layer of composite material (21), the induction heating means (15) being disposed around the first inner layer of composite material (21), and a second layer of composite material (22) disposed around the first inner layer and coaxially with said first inner layer, the induction heating means (15) being disposed preferably between the first layer and the second layer, the metallic material layer (14) wrapping an external surface of the second composite material layer (22) of the main roller body (11).

4. Calendering roller (10) according to claim 3, wherein the first layer of composite material (21) comprises: - fibers such as carbon fibers, glass fibers, silica fibers, quartz fibers, polymer fibers, boron fibers, steel fibers, ceramic fibers or aramid fibers and a resin such as an epoxy resin, a polyester resin, a phenolic resin or a ceramic resin, the second layer of composite material (22) comprises fibers such as carbon fibers, graphite fibers or metallic fibers such as steel, stainless steel, titanium or brass; and / or - a resin such as an epoxy resin, a polyester resin, a phenolic resin or a ceramic resin, and / or - the metallic material layer (14) is steel.

5. Calendering roller (10) according to claim 3 or 4, wherein the second layer of composite material (22) of the main body (11) has a thickness, taken radially with respect to the longitudinal reference axis, greater than a thickness taken radially with respect to the longitudinal reference axis, of the first layer of composite material (21) of the main body (11).

6. Calendering roller (10) according to any one of claims 1 to 5 depending at least on claim 3, wherein the induction heating means (15) comprises a working head including a coil (24) embedded in a cylindrical solid substrate (23) integral with the main roller body (11) and configured to electrically isolate the coil (24) from the first layer of composite material (21) and the second layer of composite material (22), the heating means being configured such that the coil (24) heats the metallic material layer (14) and the second composite material layer (22) when the coil (24) is in an electromagnetically active operating state.

7. Calender roll (10) according to claim 6, wherein the substrate (23) comprises, preferably is made of, a resin and / or the coil (24) comprises copper and / or steel, preferably is made of copper or steel.

8. Calendering roller (10) according to any one of claims 1 to 7, wherein the metallic material layer (14) comprises a chromium or tungsten carbide coating.

9. Device (100) for preparing an electrode in which the device (100) comprises at least one, preferably two, calendering rollers (10) according to any one of claims 1 to 8.

10. A method for manufacturing a calendering roller (10) according to any one of claims 1 to 8 comprising the following steps: - formation of the main roller body (11) equipped with the induction heating means (15) and integral with the roller drive shaft (12), and - application of a layer of metallic material (14) on the second layer of composite material (22).