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JP-7855588-B2 - Method for manufacturing electrical conductors, such as current rods, for high-temperature electrochemical devices.

JP7855588B2JP 7855588 B2JP7855588 B2JP 7855588B2JP-7855588-B2

Inventors

  • ミシェル・プランク
  • ジェロー・キュビゾル

Assignees

  • コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ

Dates

Publication Date
20260508
Application Date
20211216
Priority Date
20201221

Claims (15)

  1. A method for manufacturing an electrical conductor (100), comprising the following series of 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 hydrostatic press, and the assembly of the core (110) and the connecting terminal (130) is performed by -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 connecting 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 hydrostatic 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 within 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).

Description

This invention relates to a general field of high-temperature electrochemical devices such as fuel cells and solid oxide electrolytic cells, and more particularly to the supply of current to a stack of electrochemical cells operating at high temperatures (typically above 450°C, and even above 600°C). This invention is particularly interesting because it enables the creation of assemblies with extremely suitable mechanical rigidity, excellent resistance to oxidation, and superior conductivity, and allows the use of a wide range of materials such as cast iron and special steels. As shown in Figure 1, the solid oxide electrolytic cell 10 (SOEC, meaning "solid oxide electrolytic cell") converts a stream of water H₂O to H₂ at the cathode 11 and to O₂ (or CO₂ to CO and O₂ ) at the anode 12 under the action of an electric current within the same system. The cathode 11 and anode 12 are separated by a high-density solid oxide electrolyte 13 that operates at high temperatures and allows the passage of ions (in this case, the anion O₂- ). In the case of a solid oxide fuel cell (SOEC, meaning "solid oxide fuel cell"), the fuel cell is supplied with H₂ and O₂ , and optionally with CH₄ and air. Thus, an SOFC cell operates in the reverse way compared to an SOEC electrolytic cell, where it generates electric current and heat by being supplied with hydrogen (or natural gas, ammonia, or carbon monoxide) and air. Today, these systems can operate at high temperatures (between 600°C and 1000°C). Next, we will describe in detail the SOEC electrolytic cell in electrolysis mode ( H₂O / H₂ and O₂ pair). Generally, the electrolytic cell is formed by a stack of a continuous set of basic modules 10 (Figure 2). The basic module 10 comprises an assembly (also called an electrochemical cell) formed by an electrolyte 13 along with two electrodes 11 and 12, fastened between two interconnecting plates 14 and 15 (also called "interconnectors"). Therefore, 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 referred to as a "stack." Each interconnector plate 14 is an electron conductor, such as 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. 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 gases while separating the anode and cathode sections of two adjacent cells. 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. In SOFC mode, the anode compartment contains the fuel, while the cathode compartment contains the oxidizer. 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). 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. Regarding 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 m