Method for manufacturing electrical conductors, such as current rods, for high-temperature electrochemical devices.

Abstract

The invention relates to a method for manufacturing an electric conductor (100), such as a current rod, comprising the following successive steps: - preparing a core (110) made of a first metallic material; - preparing a sheath (120) made of a second metallic material and intended to cover a first portion of the core; - preparing a connection terminal (130) made of a third metallic material; - assembling the core (110) and the connection terminal (130) by crimping, or by crimping and brazing, or by braze welding, or by brazing; - assembling the core (110) and the connection terminal (130) with the sheath (120).

Description

Technical Field

[0001] The present invention relates to the general field of high-temperature electrochemical devices such as fuel cells and solid oxide electrolyzers, and more particularly to the supply of current to a stack of electrochemical cells operating at high temperatures (typically above 450 °C and further above 600 °C).

[0002] The present invention is particularly interesting because it enables having an assembly with very suitable mechanical robustness, and excellent resistance to oxidation and excellent conductivity, and enables the use of a wide range of materials such as cast iron and special steel.

Background Art

[0003] As shown in FIG. 1, a solid oxide electrolysis cell 10 (SOEC, meaning "solid oxide electrolysis cell") converts water stream H2O to H2 at the cathode 11 under the action of current and to O2 (or CO2 to CO and O2) at the anode 12 within the same system. The cathode 11 and the anode 12 operate at high temperatures and are separated by a high-density solid oxide electrolyte 13 that allows the passage of ions (here anions O

[0006] , ).

[0004] In the case of a solid oxide fuel cell (SOFC, meaning "solid oxide fuel cell"), the fuel cell is supplied with H2 and O2, and in some cases with CH4 and air. Thus, the SOFC cell operates in the reverse way compared to the method of the SOEC electrolyzer, which generates current and heat by being supplied with hydrogen (or natural gas, ammonia or carbon monoxide) and air.

[0005] Today, these systems can operate at high temperatures (between 600 °C and 1000 °C).

[0006] Next, we will describe in detail the SOEC electrolytic cell in electrolysis mode (H2O / H2 and O2 pairs). Generally, the electrolytic cell is formed by a stack of a continuous set of basic modules 10 (Figure 2).

[0007] The basic module 10 comprises an assembly (also called an electrochemical cell) formed by an electrolyte 13 along with two electrodes 11, 12, and fastened between two interconnecting plates 14, 15 (also called "interconnectors"). Thus, a complete electrolytic cell is an alternating stack of electrochemical cells and interconnectors. An assembly in the form of a stack of cells is generally called a "stack".

[0008] Each interconnector plate 14 is an electron conductor, for example, a metal plate, which contacts the cathode 12 of one cell on one side and the anode 21 of the next cell on the other side.

[0009] The primary role of the interconnectors 14 and 15 is to supply current to the cells. In addition, they are also intended to distribute fuel and collect the generated gas while separating the anode and cathode sections of two adjacent cells.

[0010] In electrolysis mode, the cathode compartment contains the water flow and hydrogen (and / or CO if CO2 is present at the inlet), i.e., the products of the electrochemical reaction. The anode compartment contains the exhaust gas, if present, and oxygen, i.e., another product of the electrochemical reaction in the case of both water and / or carbon dioxide electrolysis.

[0011] In SOFC mode, the anode compartment contains the fuel, while the cathode compartment contains the oxidizer.

[0012] An electrical conduction device (also called a current rod or current supply device) is connected to the end of the stack on one end and to a current source or load on the other, according to the operating mode of the device (electrolyte / fuel cell).

[0013] The proper operation of this type of stack is, among other things, -Otherwise the cell will short-circuit, but there must be proper electrical contacts, sufficient contact surface between the cell and the interconnect, electrical insulation between two consecutive interconnects, and the lowest possible ohm resistance between the cell and the interconnect is desirable. -Sealing the two compartments (oxidizer - O2) and (fuel H2 / CO / CH4 / NH3), otherwise the generated gases will recombine, leading to a decrease in efficiency and, above all, the appearance of hot spots that can damage the stack. - Proper gas distribution at both the fuel inlet and product recovery; otherwise, loss of efficiency, pressure and temperature imbalances within different basic modules, and, in some cases, damage to prohibited cells. -Requires an electrical conductive device suitable for currents of several hundred amperes, resistant to high-temperature oxidation, and capable of withstanding thermal cycling up to 900°C.

[0014] In this last point, for example, in the cited European Patent Publication No. 3 098 889 A1, the electrical conductive device 20 comprises a core 21 made of copper and protected by a sheath 22 made of stainless steel alloy (Figure 3). A whistle 23 functions as a connecting terminal, is in contact with the core 21, and is positioned at one end of the sheath 22. To manufacture such an electrical conductive device, a closed end piece completed with a tube for drawing in vacuum is positioned at the other end of the sheath. After assembly of these elements by TIC ("Tungsten Inert Gas"), a hot isostatic pressing (HIP) method is performed to achieve diffusion bonding and ensure durability of mechanical and electrical properties even after many thermal cycles.

[0015] However, this assembly does not guarantee that the surface of the whistle 23 will be perfectly plane with the flat surface of the copper core. Naturally, one or both of these parts may have defects in flatness, for example, due to geometric defects in the contact area (the enclosed area in Figures 4A and 4B) (Figure 4A) or due to cut-out narrow grooves (Figure 4B).

[0016] However, the HIP cycle cannot solve this problem because HIP as defined herein acts radially and not longitudinally. Therefore, the initially presented defect remains upon completion of the HIP.

[0017] Current can only flow through contact points. If there are defects in flatness on the contacting surfaces, the current will flow entirely through the contact points, which locally increases the current density, and the electrical resistance of the connection will subsequently be accompanied by higher heat dissipation than when the entire surface is in contact. These two phenomena can lead to material degradation, which can result in a loss of contact integrity between the two materials.

[0018] Therefore, it is essential to have optimal possible planar / planar contact (parallelism, surface condition, etc.) between the copper core and the whistle. [Prior art documents] [Patent Documents]

[0019] [Patent Document 1] European Patent Publication No. 3 098 889 A1 Specification [Overview of the project] [Problems that the invention aims to solve]

[0020] The objective of the present invention is to provide an electrical conduction device that is suitable for currents of several hundred amperes, resistant to oxidation at high temperatures, supports thermal cycling up to 900°C, and overcomes the shortcomings of the prior art.

Means for Solving the Problem

[0021] For this purpose, the present invention is a method for manufacturing an electrical conductor such as a current rod, comprising the following consecutive steps, namely - preparing a core (or rod) made of a first metal material; - preparing a sheath made of a second metal material and intended to cover a first part of the core; - preparing a whistle (also called a connection terminal) made of a third metal material; - assembling the core and the whistle; - assembling the sheath and the core, especially by fitting, wherein the assembly of the sheath at the first part of the core is carried out by the hot isostatic pressing method, and the assembly of the whistle and the core is carried out by crimping, or by crimping and brazing, or by brazing welding, or by brazing.

[0022] The present invention is basically different from the prior art in the technique of assembling the whistle and the core.

[0023] In addition, the assembly of the sheath at the first part of the core is carried out by the hot isostatic pressing method (HIP). HIP enables an optimum mechanical strength at high temperature as compared to crimping (crimping allows a decrease in mechanical holding restraint while the temperature rises).

[0024] Advantageously, the core is made of copper.

[0025] Advantageously, the sheath is made of stainless steel or an alloy or stainless nickel, and the connection terminal (or whistle) is made of a stainless alloy.

[0026] Advantageously, the whistle is made of stainless steel.

[0027] Advantageously, the sheath is made of stainless steel.

[0028] According to the first modified form, assembly is carried out by crimping. The manufacturing method is: -By inserting the core into the counterbore of the whistle, the whistle is made by covering the second part of the core, - The second portion of the core covered by the whistle is preferably compressed with a force of 20kN, -This may be carried out by the steps of covering a first portion of the core with a sheath, and then welding the sheath to the first portion of the core by a hot isohydrostatic press.

[0029] By compression, two parts can be immobilized by deformation without the aid of welding, thus avoiding areas affected by heat. This technique can be implemented without additional materials, which allows for the acquisition of assemblies at a lower cost. In addition, this technique is simple and quick to implement. It can be implemented safely. It does not form any oxides and does not cause contamination.

[0030] According to the second variant, assembly is carried out by crimping and brazing. According to a particular embodiment, the manufacturing process is - A step of positioning the brazing material in the counterbore of the whistle, -The step of inserting the core into the counterbore of the whistle, thereby covering a second portion of the core, the core being inserted into the counterbore until it comes into contact with the brazing material, - The second portion of the core covered by the whistle is preferably compressed with a force of 20kN, - The steps include: - Performing brazing to melt the brazing material, thereby obtaining a brazed joint between the whistle and the core after the molten brazing material cools; -This may be carried out by the steps of covering a first portion of the core with a sheath, and then welding the sheath to the first portion of the core by a hot isohydrostatic press.

[0031] According to another specific embodiment, the manufacturing process is - A step of positioning the brazing material in the counterbore of the whistle, -A step in which the core is inserted into the counterbore of the whistle so that the whistle covers a second portion of the core, and the core is inserted into the counterbore until it comes into contact with the brazing material, - The step of pressing the second part of the core covered by the whistle with a force of preferably 20kN, - The first part of the core is covered with a sheath, and then the sheath is welded to the first part of the core by a hot isohydrostatic pressing method at a temperature high enough to melt the brazing material, thereby performing the hot isohydrostatic pressing method simultaneously in one single step, and a brazed joint is obtained between the whistle and the core.

[0032] Brazing, in addition to crimping, improves the mechanical strength of electrical conductors. The method is simplified when brazing is performed simultaneously with hot isostatic pressing.

[0033] According to the third variant, assembly is carried out by brazing. The manufacturing method is: - A step of positioning the brazing material between the whistle and the core, - The step of performing brazing to obtain a brazed joint between the whistle and the core, - The process may be carried out by the steps of covering a first portion of the core with a sheath, wherein the core is preferably entirely covered by the sheath and the sheath is in contact with the whistle, and then welding the sheath to the first portion of the core by a hot isohydrostatic pressing method.

[0034] Brazing is a welding process that involves the diffusion of different materials in a solid state, without the addition of any filler metal. This process consists of applying high-temperature force to the parts to be welded over a given period of time.

[0035] The brazed joint between the whistle and the core is particularly resistant and durable to the heating temperatures used in high-temperature electrochemical devices.

[0036] Advantageously, the brazing material is a copper- and zinc-based alloy, which may further contain silicon. This embodiment is particularly advantageous for operating temperatures below 600°C.

[0037] According to another advantageous variant, the brazing material is a copper, zinc, and nickel-based alloy (particularly Cu / Zn / Ni / Ag) that may further contain silver, or a Cu / Mn, Cu / Mn / Ni, or Ni / Cr / P-based alloy. This embodiment is particularly advantageous for operating temperatures between 600°C and 900°C.

[0038] The present invention also relates to electrical conductors, such as current leads, obtained by the method described above.

[0039] Such an electrical conductor comprises a core, a whistle (or connector), and a sheath, the sheath covering a first portion of the core.

[0040] The sheath is welded to the first part of the core.

[0041] According to the first variant, the core may be crimped inside the whistle.

[0042] In the second variant, the core is crimped into the whistle and brazed together with the whistle.

[0043] According to the third variant, the core is brazed to the whistle using a brazed joint, the brazed joint being preferably a Cu / Zn / Ni / Ag, Cu / Mn, Cu / Mn / Ni, or Ni / Cr / P based alloy.

[0044] Advantageously, the sheath is made of stainless steel, or an alloy or stainless nickel, and the connector (or whistle) is made of a stainless alloy.

[0045] Such devices, as in the case of electrochemical devices such as fuel cells and solid oxide electrolytic cells, possess extremely optimal electrical and mechanical properties even after numerous high-temperature operating cycles.

[0046] Other features and advantages of the present invention will arise from the following complementary description.

[0047] Needless to say, this complementary description is provided merely as an example of the objectives of the present invention and should not be construed as a limitation of those objectives.

[0048] The present invention will be better understood by referring to the accompanying drawings and reading the description of the embodiments presented for illustrative purposes only and for non-limiting purposes. [Brief explanation of the drawing]

[0049] [Figure 1] This is a diagram illustrating the operating principle of a high-temperature electrolytic cell (SOEC), which has already been described previously. [Figure 2] This is a schematic diagram illustrating the main components of a high-temperature electrolytic cell (SOEC), which has already been described previously. [Figure 3] This is a schematic diagram illustrating the disassembled assembly of the current lead, which I have already described previously. [Figure 4A] This is a schematic diagram illustrating an example of a defect in the current leads of the whistle / core interface, which I have already described previously. [Figure 4B]This is a schematic diagram illustrating an example of a defect in the current leads of the whistle / core interface, which I have already described previously. [Figure 5] This diagram schematically shows an exploded assembly diagram of a current lead according to a specific embodiment of the present invention. [Figure 6] This figure schematically shows a cross-sectional view of the current lead shown in Figure 5. [Figure 7] This figure schematically shows the pressure applied to the peripheral area of ​​the crimping region of a current lead during crimping, according to a specific embodiment of the present invention. [Figure 8] This figure schematically shows an exploded assembly diagram of a current lead according to another specific embodiment of the present invention. [Figure 9] This figure schematically shows a cross-sectional view of the current lead shown in Figure 8. [Modes for carrying out the invention]

[0050] Different parts shown in the drawings are not necessarily depicted according to a uniform scale in order to make the drawings easier to read.

[0051] Next, even if the description refers in more detail to the assembly of current rods, the present invention is generally replaceable for assemblies of highly resistant metals and / or alloys, such as cast iron and special steels. More specifically, the present invention finds applications for assemblies of steels with low weldability, assemblies of different metals and alloys, assemblies of galvanized steel and stainless steel, assemblies of copper and its alloys, assemblies of aluminum and its alloys, or for forming assemblies with little or no deformation.

[0052] Referring to Figures 5 through 9, a method for manufacturing electrical conductors, and more specifically, current rods (also called current leads), is described.

[0053] The components to be assembled to form the current rod are a core 110 made of a first metal material, a sheath 120 made of a second material, and a whistle 130 made of a third material.

[0054] Whistle 130 is also commonly referred to as a connector.

[0055] The core 110 is an optimal electrical conductor, but is sensitive to oxidation, and is made of, for example, nickel, silver, copper, or a copper alloy. Preferably, the core 110 is copper. For example, it may be composed of Cuc1 or Cua1 copper. The core 110 is a rod.

[0056] The core 110 is inserted into the sheath 120. The sheath 120 is a tube. The sheath has a first end and a second end. On the side of the first end, the sheath 120 covers the first portion 111 of the core 110 (core / sheath overlap region). Due to its property of higher resistance to oxidation than that of the core 110, it ensures protection of the core against an oxidizing atmosphere. In this way, it is possible to benefit from the better conductivity of the core material by maximizing the service life of the assembly in an oxidizing atmosphere. For example, the sheath 120 is made of stainless steel or a stainless-nickel alloy. The second end is intended to be secured with an end piece not shown.

[0057] The whistle 130 is intended to be connected to the plate of the electrolytic cell. It acts as a connecting leg, ensuring an electrical connection with the electrolytic cell. It has a shape complementary to the plate of the electrolytic cell to which it is fastened. The whistle 130 may be drilled perpendicular to the axis of the sheath (through hole 131) so that it is screwed onto the stack of electrolytic cells. The whistle 130 may have a geometric shape other than that illustrated in the drawings. For example, it may be cylindrical and intended to be fitted into a hole or crimped between two halves of an outer shell fixed to a device to which power is to be supplied.

[0058] After being assembled to the first end of the sheath 120, the whistle 130 seals this end airtight, thereby preventing gas from passing through.

[0059] Preferably, the whistle 130 is made of a stainless steel alloy, such as nickel-chromium-iron alloy or Inconel® 600.

[0060] Prior to the assembly of the parts, the surface preparation is advantageously carried out by one means or by a set of suitable means (in particular, sandblasting, brushing, pickling with detergent and / or solvent).

[0061] According to the present invention, the assembly of the core 110, sheath 120, and whistle 130 for forming an electrical conductor may be carried out according to different production processes, namely crimping, or crimping and brazing, or brazing welding, and hot isostatic pressing.

[0062] Next, the first embodiment (assembly by crimping) shown in Figures 5, 6, and 7 will be described in more detail. In this embodiment, a whistle 130 with a counterbore is advantageously used. The counterbore 132 is a blind hole with a flat bottom. The counterbore 132 may have a depth of, for example, 8 to 20 mm. The diameter of the counterbore 132 depends on the diameter of the core 110. The core 110 is inserted into the counterbore. After assembly, the counterbore 132 covers a second portion 112 of the core 110 (core / whistle overlap region). Advantageously, a gap of 0.05 is selected between the core and the counterbore of the whistle. Advantageously, the wall of the counterbore 132 is provided with through holes 133 to allow air to escape from the core 110 during insertion of the whistle 130 into the counterbore 132.

[0063] After the core 110 is inserted into the counterbore 132, crimping is performed by applying pressure to the periphery of the core / whistle overlap region 112 (Figure 7). Crimping may be performed with an electromechanical crimping tool. A crimping force is then applied according to the effective dimensions of the assembly and the mechanical properties of the materials to be crimped. In the cases described herein (Inconel 600 tube, diameter within 10 mm), a force within 20 kN is sufficient to achieve adequate crimping.

[0064] Subsequently, the sheath 120 is positioned to cover the first portion 111 of the core 110. Thus, the core 110 is completely covered on one side by the sheath 120 and on the other side by the whistle 130. After the whistle 130 and the sheath 120 come into contact, they are welded together in a manner advantageous for sealing the assembly.

[0065] The crimping is performed at room temperature (typically between 20 and 25°C), and the molecular structure of the copper core 110 does not deform upon heating, which ensures an extended service life. Crimping is a durable assembly technique.

[0066] Next, the second embodiment (assembly by crimping and brazing) will be described in more detail.

[0067] According to this second embodiment, the process continues as in the first embodiment by further positioning the brazing material within the counterbore of the whistle 130 before inserting the core 110. Preferably, the brazing material is positioned to cover the flat bottom of the counterbore 132. The brazing material 132 (also called the filler material) may be in the form of a pellet or paste that can be spread. After the core 110 is inserted into the counterbore 132, the brazing material comes into contact with the two parts to be assembled (i.e., the whistle and the core). The placement of the brazing pellets during installation with a thickness preferably between 25 μm and 200 μm, and even more preferably 100 μm, advantageously allows for addressing defects, creating a connection between Inconel and copper, and ensuring electrical continuity.

[0068] The brazing step is, - The steps include: heating two parts 110, 130 and the brazing material to an assembly temperature higher than the melting temperature of the brazing material in order to melt the brazing material, and maintaining the assembly temperature for a holding time, wherein the brazing temperature depends on the selected brazing alloy, and is preferably higher than the temperature at which the assembly is operated, i.e., 900°C in the case of the current bar of an electrolytic cell / SOFC fuel cell type system, and - This is carried out by the steps of cooling the assemblies to form a brazed joint between the whistle 130 and the core 110, and then assembling them.

[0069] Advantageously, brazing is performed during a hot isohydrostatic press.

[0070] A third embodiment (assembly by brazing-oxygen-acetylene welding process), shown in Figures 8 and 9, is described in more detail below.

[0071] In this embodiment, the whistle 130 does not include a counterbore. It has a shape complementary to the sheath 120, and the sheath 120 fits around one end of the whistle 130.

[0072] According to this third embodiment, the assembly is as follows: - A step of positioning the brazing material 140 between the core 110 and the whistle 130, - The step of performing brazing welding of the thus obtained assembly in order to have an assembly having a core 110 connected to the whistle 130 by a brazed joint, -This is carried out according to the steps of inserting the core 110, the brazed joint, and a portion of the whistle 130 into the sheath 120.

[0073] Preferably, the brazing material 140 is an alloy of copper and zinc. This alloy may further contain silicon.

[0074] For example, a Cu-Zn-Ag alloy commercialized by Castolin Eutectic under reference 16 XFCR® is selected.

[0075] According to another embodiment, the assembly of the whistle 130 and the core 110 may be carried out by brazing (without crimping).

[0076] After the core 110, sheath 120, and whistle 130 are assembled (by crimping and / or by brazing or brazing welding), the assembly is advantageously subjected to a hot isostatic pressing step to weld the sheath 120 to the core 110, thereby enhancing the mechanical strength of the final assembly.

[0077] According to a particular embodiment of the method, diffusion welding by hot isohydrostatic pressing is performed. - A step of TIG ("tungsten inert gas") welding a degassing pipe onto the second end of the sheath 120, wherein the second end of the sheath 120 is the opposite end that contacts the whistle 130, and - A step of TIG welding a cap (or fastener end piece) to seal this second end. Preferably, the end piece and its tube are made of a stainless steel alloy, for example, AISI 316L. The end piece seals the second end of the sheath 120 airtight, except at the location of the degassing center tube through which it passes and across and communicates with the sheath 120. - A step of placing the sheath under vacuum by pumping through the tube at the first end, which allows for the removal of gas present between the core 110 and the sheath 120. - The step of sealing this tube, for example by pinching off the sheath 120, - The process includes the step of applying a diffusion welding cycle to the assembly by hot isostatic pressing (HIP).

[0078] Advantageously, the welding cycle using HIP is - The step of bringing the assembly formed by the core 110 and the sheath 120 to a temperature between 600°C and 1060°C, preferably between 800°C and 1000°C, more preferably between 900°C and 1000°C, and particularly to 920°C, - The step of applying a pressure to the sheath 120 that is between 500 bar and 1500 bar, preferably between 800 and 1200 bar, and particularly between 1020 bar, - A step of applying pressure and temperature levels for a period of 30 minutes to several hours, preferably for 1 to 3 hours, and particularly for 2 hours, -This may include the step of letting the assembly cool and then reducing the pressure.

[0079] Advantageously, the current rod 100 is, -This defines a casing for air circulation within a defined volume, - An electrochemical device housed within a casing (preferably consisting of a high-temperature steam electrolytic cell or a high-temperature fuel cell), - A stack of basic electrochemical cells, or a stack in which each cell contains an electrolyte interposed between the cathode and anode, and is connected in a continuous manner between two electrical terminals. - Used in an electrochemical system that includes an electrochemical device having two electrical conductors, as previously described, connected to two electrical terminals, respectively.

[0080] An exemplary and non-restrictive example of one embodiment: In this example, 16 XFCR® (Cu / Zn / Ag / Ni) brazing material, commercialized by Castolin Eutectic, is used to create a brazed joint between a whistle 130 made of Inconel® 600 alloy and a core 110 made of copper.

[0081] The brazing material 140 is supplied in the form of a stick coated with an elastic stripper. The stick has remarkable flexibility, which allows for excellent visibility of the molten pool during assembly.

[0082] Brazing material 140 has the following characteristics: 1% silver / 9% nickel, solidus temperature 885°C, liquidus temperature 915°C, tensile strength 550 MPa, elastic limit 236 MPa, elongation 35%, density 8.4, and hardness 120 HB.

[0083] Such brazing material 140 has high mechanical properties and is particularly suitable for brazing steel and cast iron.

[0084] The gap between the core 110 and the whistle 130 may be, for example, in the range of up to 0.1 mm, because the alloy has excellent properties in terms of capillary action.

[0085] After brazing is performed, the process proceeds with the installation of the current rod (fitting the sheath 120 into the core 110), followed by a hot isostatic pressing (HIP) cycle to perform diffusion welding of different materials between them without adding filler metal. [Explanation of Symbols]

[0086] 10 Basic Modules 11, 12 electrodes 13 Electrolytes 14, 15 Interconnection plates 20 Electrical Conduction Devices 21 cores 22 Sheath 23 Whistle 100 Current Rods 110 cores 111 Part 1 112 Part 2 120 Sheath 130 Whistle 131 Through hole 132 counterbore 133 Through hole 140 Brazing materials

Claims

1. A method for manufacturing an electrical conductor (100), comprising the following consecutive steps, namely - A step of preparing a core (110) made of a first metal material, - A step of preparing a sheath (120) made of a second metallic material and intended to cover the first portion (111) of the core, - A step of preparing a connecting terminal (130) made of a third metallic material, wherein the connecting terminal (130) is intended to be fastened to an electrolytic cell plate, and the connecting terminal (130) has a shape complementary to the electrolytic cell plate, - The step of assembling the core (110) and the connection terminal (130), - The step of assembling the core (110) and the connection terminal (130) with the sheath (120), The sheath (120) is welded to the first portion (111) of the core (110) by a hot isohydrostatic pressing method, and The assembly of the core (110) and the connection terminal (130) is as follows: -By crimping, or -By crimping and brazing, or -By brazing, - A method characterized by being carried out by brazing.

2. The assembly of the core (110) and the connecting terminal (130) is carried out by crimping, and the method is as follows: -By inserting the core (110) into the counterbore (132) of the connection terminal (130), the connection terminal (130) covers the second portion (112) of the core (110), - The step of crimping the second portion (112) of the core (110) covered by the connection terminal (130) with a force of 20kN, The method according to claim 1, characterized by being carried out by the steps of: covering the first portion (111) of the core (110) with the sheath (120); and then welding the sheath (120) to the first portion (111) of the core by a hot isohydrostatic press.

3. The assembly of the core (110) and the connecting terminal (130) is carried out by crimping and brazing, and the method is as follows: - A step of positioning the brazing material in the counterbore (132) of the connection terminal (130), -The step of inserting the core (110) into the counterbore (132) of the connection terminal (130) so that the connection terminal covers the second portion (112) of the core (110), - The step of crimping the second portion (112) of the core (110) covered by the connection terminal (130) with a force of 20kN, - A step in which brazing is performed to melt the brazing material, thereby obtaining a brazed joint between the connecting terminal (130) and the core (110) after the brazing material has cooled, The method according to claim 1, characterized by being carried out by the steps of: covering the first portion (111) of the core (110) with the sheath (120); and then welding the sheath (120) to the first portion (111) of the core (110) by a hot isohydrostatic press.

4. The assembly of the core (110) and the connecting terminal (130) is carried out by crimping and brazing, and the method is - A step of positioning the brazing material in the counterbore (132) of the connection terminal (130), -The step of inserting the core (110) into the counterbore (132) of the connection terminal (130) so that the connection terminal (130) covers the second portion (112) of the core (110), - The step of crimping the second portion (112) of the core (110) covered by the connection terminal (130) with a force of 20kN, The method according to claim 1, characterized in that -the first portion (111) of the core (110) is covered with the sheath (120), and then the sheath (120) is welded to the first portion (111) of the core (110) at a temperature sufficiently high to melt the brazing material by a hot isohydrostatic pressing method, thereby performing the hot isohydrostatic pressing method simultaneously and obtaining a brazed joint between the connecting terminal (130) and the core (110).

5. The assembly of the core (110) and the connecting terminal (130) is carried out by brazing, and the method is as follows: - A step of positioning the brazing material (140) between the connection terminal (130) and the core (110), - The step of performing brazing to obtain a brazed joint between the connecting terminal (130) and the core (110), The method according to claim 1, characterized in that it is carried out by the steps of: covering the first portion of the core (110) with the sheath (120), wherein the sheath (120) is in contact with the connecting terminal (130); and then welding the sheath (120) to the first portion (111) of the core (110) by a hot isohydrostatic press.

6. The method according to claim 5, characterized in that the brazing material is a copper, zinc, and nickel-based alloy that may further contain silver.

7. The method according to any one of claims 1 to 6, characterized in that the core (110) is made of copper.

8. The method according to any one of claims 1 to 7, characterized in that the sheath (120) is made of stainless steel or a stainless-nickel alloy, and the connecting terminal (130) is made of a stainless steel alloy.

9. The method according to any one of claims 1 to 8, characterized in that the connection terminal (130) is made of stainless steel.

10. The method according to any one of claims 1 to 9, characterized in that the sheath (120) is made of stainless steel.

11. The electrical conductor (100) comprises a core (110), a sheath (120), and a connector (130), wherein the sheath (120) covers a first portion (111) of the core (110), and the connector (130) is intended to be fastened to an electrolytic cell plate, and the connector (130) has a shape complementary to the electrolytic cell plate. The sheath (120) is welded to the first portion (111) of the core (110) by a hot isohydrostatic pressing method, and - The core (110) is crimped to the connection terminal (130), or - The core (110) is crimped and brazed to the connection terminal (130), or - An electrical conductor (100) characterized in that the core (110) is brazed to the connection terminal (130) using a brazed joint, and the brazed joint is a copper, zinc, and nickel-based alloy which may further contain silver.

12. The electrical conductor (100) according to claim 11, characterized in that the sheath (120) is made of stainless steel or a stainless-nickel alloy, and the connecting terminal (130) is made of a stainless steel alloy.

13. The electrical conductor (100) according to either claim 11 or 12, characterized in that the core (110) is made of nickel, silver, copper, or a copper alloy.

14. The electrical conductor (100) according to any one of claims 11 to 13, characterized in that the core (110) is inserted into and crimped therein of the counterbore (132) of the connecting terminal (130), and the connecting terminal (130) covers the second portion (112) of the core (110).

15. The electrical conductor (100) according to any one of claims 11 to 13, characterized in that the core (110) is inserted into the counterbore (132) of the connecting terminal (130), crimped and brazed therein, and the connecting terminal (130) covers the second portion (112) of the core (110).

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