Method for manufacturing an electric current sensor by additive manufacturing

Abstract

TITLE: Method for manufacturing an electric current sensor by additive manufacturing. The invention relates to a method for manufacturing an electric current sensor (ECS) comprising the following steps: a) providing a substrate (SBT) made of metal or metal alloy, b) creating a non-through cavity (CVT) in said substrate such that said cavity separates the substrate into two zones (Z1, Z2), c) creating, by additive manufacturing, a resistive element (ER) in said cavity (CVT), d) annealing the assembly thus obtained, e) removing a portion of the substrate (SBT) to leave only the resistive element (ER) between the two zones (Z1, Z2) of the substrate, and f) defining, within each zone (Z1, Z2), a connection terminal (BCE1, BCE2) to obtain said electrodes (PEL, DEL). Figure for the abstract: Fig. 2

Description

Title of the invention: Method for manufacturing an electric current sensor by additive manufacturing Technical field of the invention

[0001] The invention relates to the field of manufacturing electric current sensors, for example an electric shunt. Technical background

[0002] A known electrical shunt is shown in [Fig.l].

[0003] Typically, an electrical measuring shunt 1 is composed of a calibrated resistive element 2, electrodes 3, 3', electrical connection terminals 4, 4' and measurement terminals 5, 5' defined on the electrodes 3, 3' respectively. The electrical connection terminals 4, 4' allow the passage of an electric current under the effect of a potential difference (voltage), which can be measured between the measurement terminals 5, 5'. Thanks to the calibrated value of the resistance of the resistive element 2 and the voltage measurement at the measurement terminals, the electric current passing through the electrical measuring shunt 1 can be deduced, using Ohm's law.

[0004] The calibration of the resistive element 2 is generally ensured by localized machining of the resistive element. For example, reference may be made to WO 2017 / 065144 A1 in which it is proposed to make notches on the resistive element 2 while it is electrically powered, in order to adjust the value of its resistance (in-situ calibration, during measurement). Alternatively, the calibration of the resistive element 2 can also be done by mechanical adjustment during the assembly of the electrical shunt 1, by geometrically controlling the contact surface between two resistive elements. This is for example what is proposed in WO 2019 / 190144 A1 or WO 02 / 56320 A1

[0005] The resistive element 2 is generally made of a copper-based alloy. The copper-based materials used for the resistive element 2 typically have resistivities of between 20 and 50 pQ.cm, and maximum temperature coefficients of resistance (variation of resistivity as a function of temperature) of ± 30.106 .K '. The composition of these alloys (copper, manganese, nickel, tin, iron, silicon) gives them electrical characteristics which guarantee the accuracy and reliability of the measurement over an operating temperature range of 0°C to 175°C. For example, reference may be made to WO 2022 / 044611 Al or WO 2022 / 030071 AL

[0006] Furthermore, the resistive element 2 is usually brazed to the electrodes 3, 3' with Silver 6, 6'. This assembly by brazing with Silver limits the use to certain materials. Therefore, the electrodes 3, 3' are mainly made of Copper or with a Copper-based alloy. It should be noted that the assembly of the element resistive 2 with electrodes 3, 3', has been the subject of numerous publications. Examples include WO 2011 / 068205 Al, WO 2017 / 110354 Al and WO 2015 / 080333 Al.

[0007] The assembly of the electrical connection terminals 4, 4' to the electrodes 3, 3' has also been the subject of publications. In particular, WO 2019 / 097924 A1, WO2019 / 097925 A1 and KR10-2016-0101251 may be cited, with in particular proposals for reducing or eliminating the contact resistance between the electrical connection terminals and the electrodes.

[0008] It is therefore noted that there are multiple ways of assembling the various elements of the electrical measuring shunt, such as: pressure bonding, soldering, welding (electrical resistance, laser, electron beam) and metal molding. Each assembly process must be compatible with the materials (resistive element, electrode and measuring terminal), ensure good electrical conductivity between the assembled elements (minimize contact resistance), and guarantee the mechanical strength of the assembly of the electrical measuring shunt.

[0009] It should also be noted that the geometries and dimensions of the resistive elements have an influence on the thermal and electrical behavior of the electrical measuring shunts.

[0010] We thus find solid bar shapes, shapes based on a multitude of thin bars (WO 2017 / 065144 Al, WO 2019 / 190144A1, CN209231398U), or rod or tube shapes (WO 2018 / 150870 Al, WO 2013 / 005824 Al, WO 2011 / 068205 Al). In particular, the tube shape makes it possible to limit losses by Joule effect by taking advantage of the skin effect when alternating currents pass.

[0011] In all cases, the materials of the resistive elements being selected according to their electrical properties (resistivity and temperature coefficient of resistance), this conditions the choice of the materials of the electrodes, very largely copper-based. Indeed, the resistive element and the electrodes must be able to be assembled and have compatible electrical and thermal properties, without taking into account the contact resistance induced between the different elements of the measuring shunt.

[0012] Also, the manufacturing processes (assembly and calibration techniques) are factors limiting the geometric and dimensional optimization of electrical measurement shunts. The contact areas between the resistive elements, the electrodes, the connection and measurement terminals must all be accessible to allow assembly by brazing, welding or molding. In addition, the re-machining of the resistive element to perform the calibration constitutes an additional post-manufacturing step.

[0013] An objective of the invention is to propose a method for manufacturing an electric current sensor which does not have at least one of the aforementioned drawbacks. Summary of the invention

[0014] To solve this objective, the invention proposes a method of manufacturing an electric current sensor comprising the following steps: (a) providing a metal or metal alloy substrate, b) making a non-through cavity in said substrate so that said cavity separates the substrate into two zones, c) producing, by additive manufacturing, a resistive element in said cavity, d) annealing the assembly thus obtained, e) removing part of the substrate to leave only the resistive element between the two areas of the substrate, and f) defining, within each zone, a connection terminal to obtain said electrodes.

[0015] The method according to the invention may comprise at least one of the following additional steps, taken alone or in combination:

[0016] - the substrate provided in step a) is made of Aluminum, Copper or an alloy based on of Copper;

[0017] - the cavity produced in step b) is obtained by machining the substrate;

[0018] - step c) is carried out by cold spraying, advantageously at in pressure lower than 15 bar;

[0019] - step d) is carried out at a temperature between 400 and 600°C for a duration between 5 and 15 minutes;

[0020] - the method comprises an additional step consisting of producing a terminal of measurement in each of the two electrodes;

[0021] - the resistive element does not undergo any machining step, in particular to adapt the value of its resistivity;

[0022] - the substrate provided in step a) is a solid cylinder;

[0023] - the substrate provided in step a) is a solid parallelepiped;

[0024] - the sensor is an electrical shunt. Brief description of the figures

[0025] Other objects and characteristics of the invention will appear more clearly in the following description, given with reference to the appended figures, in which:

[0026] [Fig.2] represents an electrical shunt, of hollow cylindrical shape, obtained with the manufacturing method according to the invention;

[0027] [Fig.3] represents a manufacturing method in accordance with the invention of the electrical shunt shown in [Fig.2];

[0028] [Fig.4a] is a diagram showing an installation for implementing a cold spray additive manufacturing process at low pressure ;

[0029] [Fig.4b] is a diagram showing an installation for implementing a high-pressure cold spray additive manufacturing process;

[0030] [Fig.5a] represents a substrate capable of being used to begin the manufacturing process according to the invention;

[0031] [Fig.5b] represents the substrate of [Fig.5a] after being machined;

[0032] [Fig.5c] represents the assembly formed after deposition by additive manufacturing of a resistive element in a non-through hole of the machined substrate of [Fig.5d];

[0033] [Fig.5d] represents the electrical shunt finally obtained after annealing and piercing through and through the whole of [Fig.5c];

[0034] [Fig.6] shows the electrical shunt after adding measuring terminals;

[0035] [Fig.7] shows an electrical shunt, of the “busbar” type, obtained with the process manufacturing process according to the invention. Detailed description of the invention

[0036] The following description is made in the case where the electric current sensor is an electric shunt. However, the invention is not limited to the manufacture of an electric shunt.

[0037] [Fig.2] is an example of an embodiment of an electrical shunt SHE, in this case of hollow cylindrical shape, obtained according to the method according to the invention.

[0038] The electrical shunt SHE comprises a first electrode PEL, a second electrode DEL and a resistive element ER between the two electrodes PEL, DEL. Each PEL electrode has an associated connection terminal BCE1, BCE2 respectively in this case located at the ends of the electrical shunt. A measuring terminal BMI, BM2 is also provided on each electrode PEL, DEL. In this embodiment, the electrodes PEL, DEL as well as the resistive element form hollow cylinders.

[0039] [Fig. 3] schematically represents the different stages of the manufacturing process of an electric current sensor such as an SHE electric shunt, in particular that which is represented in [Fig. 2], namely: (a) provide a metal or metal alloy SBT substrate, b) producing a non-through CVT cavity in said substrate such that said cavity separates the substrate into two zones Z1, Z2, c) producing, by additive manufacturing, a resistive element ER in said CVT cavity, d) carrying out an annealing of the assembly thus obtained at the end of step c), e) removing a part of the SBT substrate to leave only the resistive element ER between the two zones Z1, Z2 of the substrate, and f) define, within each zone Zl, Z2, a connection terminal BCE1, BCE2 to obtain said electrodes PEL, DEL.

[0040] The SBT substrate provided in step a) may be made of Aluminum, Copper or a Copper-based alloy and more generally of any electrically conductive metals or metal alloys. The method according to the invention, due to the use of an additive manufacturing step, allows in particular the use of a wider range of metals or metal alloys, while limiting the contact resistances between the resistive element ER and the PEL, DEL electrodes. It is therefore in particular possible to use Aluminum, which has the advantage of being much lighter than Copper-based alloys. This may be important for certain applications.

[0041] The substrate provided in step a) is shown in [Fig.5a]. It is a solid cylinder.

[0042] The non-through CVT cavity produced in step b) is for example obtained by machining the SBT substrate. This will be the case in particular when a solid cylindrical substrate is provided in step a), from which material will then be removed to obtain the desired final shape of the SHE electrical shunt. Since the CVT cavity is non-through, there remains at this stage a POR portion of substrate connecting two zones Z1, Z2 of this same substrate, which are located on either side of the CVT cavity.

[0043] According to an alternative embodiment, it is possible to envisage merging steps a) and b) by carrying out additive manufacturing of the SBT substrate in the desired shape. This can be carried out by a process called “Cold Spray” according to English terminology (or “cold spraying” in French), or by a process called “direct energy deposition”.

[0044] At the end of step b), a substrate is obtained as defined in [Fig. 5b]). As can be seen in this figure, the substrate in this case comprises a holding rod TM which is only useful for handling the substrate SBT during certain steps of the manufacturing process. This holding rod TM is intended to disappear during the remainder of the manufacturing process.

[0045] To implement step c), different additive manufacturing techniques are possible.

[0046] It is thus possible to advantageously use the "Cold Spray" process according to Anglo-Saxon terminology, or "cold spraying" in French. The "Cold Spray" process (also known as "Gas Dynamic Spraying" or "Kinetic Spraying Process" according to Anglo-Saxon terminology) is a coating deposition process based on the supersonic projection of solid powder at a temperature below the melting temperature of the materials forming the powder grains. It is the kinetic energy acquired by the powder grains which makes it possible to plastically deform the materials constituting them in order to ensure the adhesion of the deposit. The tem The temperatures used in this process are lower than the temperatures used in other thermal spraying processes.

[0047] [Fig.4a] shows an installation for implementing a “Cold Spray” deposition process, operating at low pressure (better known by the acronym LPCS for “Low Pressure Cold Spray” in English terminology).

[0048] More specifically, the installation comprises a CMP compressor for injecting a carrier gas, for example air or nitrogen, into a heater or heat exchanger ECH. The outgoing gas is thus pressurized, typically to pressures below 15 bar (low pressure) and at a temperature, typically below 1000°C and in any case below the melting temperature of the material forming the powder grains, before entering a nozzle TY, typically a Laval nozzle. The nozzle TY expands the previously heated and pressurized gas and thus accelerates the speed of the gas jet to make it supersonic. A powder reservoir RES allows powder to be injected into the nozzle TY, for example downstream of the nozzle neck, with grains of the chosen material.At the nozzle outlet, the powder is projected against an SBT substrate to deposit an RVT coating which can be in the form of one or more successive layers. Furthermore, the or each layer of the coating can be deposited in different ways, for example in a spiral, by rings of different diameters or even along parallel generators, etc. Conventionally, particles of 5 to 50 pm can be projected at speeds of approximately 600 m / s. LPCS is generally used for the projection of “soft” materials. The material projected in powder form can be mixed with alumina (also in powder form) to increase the yield and density of the deposit.

[0049] As regards the LPCS, one can for example refer to the article by Shuo Yin, Pasquale Cavalière, Barry Aldwell, Richard Jenkins, Hanlin Liao, Wenya Li, Rocco Lupoi, “Cold spray additive manufacturing and repair: Fundamentals and applications”, Additive Manufacturing, Volume 21, 2018, Pages 628-650, ISSN 2214-8604, https: / / doi.Org / 10.1016 / j.addma.2018.04.017.

[0050] [Fig.4b] shows another installation for implementing a “Cold Spray” deposition process, operating at high pressure (better known by the acronym HPCS for “High Pressure Cold Spray” in English terminology).

[0051] More specifically, the installation comprises a pressurized gas cylinder BGP for injecting a carrier gas, for example air, nitrogen or helium, into two parallel circuits, one comprising a heater or heat exchanger ECH, the other comprising a powder reservoir RES arranged to inject powder into the circuit concerned. The two circuits are then combined before entering a TY nozzle, for example a Laval nozzle. The gas from the circuits is thus pressurized, typically to pressures greater than 15 bar (high pressure) and under temperature, which can here exceed 1000°C while remaining at a temperature lower than the melting temperature of the material forming the powder grains, before entering the TY nozzle. The TY nozzle allows the previously heated and pressurized gas to be expanded and thus accelerates the speed of the gas jet to make it supersonic. At the outlet of the TY nozzle, the powder is projected against an SBT substrate to deposit an RVT coating which can be in the form of one or more successive layers. Furthermore, the or each layer of the RVT coating deposited can be done in different ways, for example in a spiral, by rings of different diameters or along parallel generatrices, etc.Typically, particles from 5 to 50 pm can be projected at speeds that can exceed 1000 m / s. HPCS is generally used for projecting “hard” materials, such as titanium.

[0052] In the context of the applications targeted by the invention, it will be advantageous to use a “Cold Spray” of the LPCS (low pressure) type, typically between 4 and 10 bars and more particularly between 4 and 8 bars, with a powder with a particle size of between 5 and 25 μm. Furthermore, the deposition of this powder is then advantageously carried out at a temperature of between 400°C and 600°C. The carrier gas used to project the powder against the substrate, such as air, is particularly well suited.

[0053] The material constituting the powder and therefore the resistive element ER may be a metal, for example Copper, Nickel, Aluminum or Zinc, or a copper-based metal alloy, for example Manganin, Noventin, Zeranin or Constantan. In practice, the use of Manganin, with a particle size of between 5 and 25 μm, is particularly well suited for the applications targeted within the scope of the invention, in particular for the electrical shunt SHE shown in [Fig. 2]. In particular, this Manganin can then be co-projected with alumina (advantageously with a particle size less than or equal to 25 pm to increase the yield and density of the deposit. In the case of co-projection, the quantity of alumina, non-zero, can represent up to 40% by mass of the Alumina + Manganin powder mixture. The increase in yield means that the ratio between the quantity of material deposited on the quantity of material projected increases.Increasing the density of the deposit makes it possible to reduce the presence of defects (porosity, cracks, etc.) and therefore to increase the mechanical strength properties and / or the electrical and thermal properties of the deposit. It is also possible to plan a sandblasting step with alumina powder of large particle size, for example 250 microns, before the projection of the powder to manufacture the ER resistive element, in order to increase the roughness of the . substrate and consequently the mechanical attachment of the resistive element ER on the SBT substrate intended to form the PEL, DEL electrodes.

[0054] Alternatively, still within the scope of the applications targeted by the invention, it is possible to start from a powder with a particle size of between 15 and 45 μm while operating at high pressure, namely between 10 and 60 bars. The associated temperatures can then be between 400 and 600°C.

[0055] Generally speaking, still within the scope of the applications targeted by the invention, it is therefore possible to operate with a “Cold Spray” type process with a pressure ranging from 4 to 60 bars (low pressure ranging from 4 to 10 bars or high pressure ranging from 10 to 60 bars), with temperatures likely to cover a wide range ranging from 20°C to 1000°C, in particular depending on the nature of the material forming the powder (listed above) and its particle size (likely to range from 5 to 65 μm), with a vector gas such as air, Argon or Helium.

[0056] Additive manufacturing techniques other than “Cold Spray” can be used. Thus, it is possible to envisage additive manufacturing of the resistive element ER by a technique called “Direct Energy Deposition” (DED) and / or by a technique called “Laser Powder Bed Fusion (LPBF)” which, like the “Cold Spray” technique, allow the composition of the deposit to be controlled and varied during manufacturing.

[0057] Several strategies for obtaining the resistive element ER are then possible: - Deposition of the resistive alloy (Cold Spray, DED, FLPL): the composition and properties are fixed, - Combinatorial deposition with direct fusion (DED, FLPL), allows the creation of a custom alloy with remelting of alloy precursors (eg: Cu, Mn, Ni, Sn, Fe, Si), - Combinatorial deposition with localized post-process (“Cold Spray” + friction or laser post-treatment): allows a deposit to be obtained containing all the alloy precursors and a post-treatment to be applied to obtain the desired electrical properties in a localized manner.

[0058] Thus, the composition and composition gradients of the resistive elements are determined according to the targeted electrical properties without being restricted to the strict (commercial) alloys generally used.

[0059] At the end of step c), we arrive at a set as shown in [Fig.5c].

[0060] The annealing carried out in step d) may aim to restore the mechanical and electrical properties of the materials or to release the mechanical stresses and increase the strength of the deposit. Depending on the case, the annealing conditions are not the same. Thus, the annealing can be carried out at a temperature between 150 and 300°C for a period of time ranging from 15 to 60 minutes to restore the mechanical and electrical properties materials (restoration annealing). Thus, annealing can also be carried out at a temperature of around 300°C for a period of 1 hour or more, to release mechanical stresses (recrystallization annealing) and increase the strength of the deposit. Annealing can be carried out in air or under a controlled atmosphere. Typically, for copper materials (such as manganin), annealing can be carried out in air or under a controlled atmosphere, at high temperatures up to 600°C (recrystallization annealing), or at lower temperatures of around 200°C (restoration annealing), knowing that the melting temperature of the material forming the substrate should also be taken into account (for example, for aluminum, the melting temperature is 660°C but it can nevertheless begin to flow under stress from 450°C).

[0061] Once the annealing has been carried out, during a step e) of the method according to the invention, part of the SBT substrate is removed to leave only the resistive element ER between the two zones Z1, Z2 of the substrate. Applied to the manufacture of the electrical shunt SHE of [Fig. 2], this step consists more precisely in piercing right through the assembly recovered after the annealing. This makes the holding rod TM disappear, but also the connection zone of the SBT substrate between these two zones. This also makes it possible, incidentally, in accordance with step f) of the method according to the invention, to create the two connection terminals BCE1, BCE2 on the zones Z1, Z2 in order to define the electrodes PEL, DEL.

[0062] The assembly obtained at the end of step f) is shown in [Fig.5d].

[0063] Advantageously, in an additional step, it only remains to create measurement terminals BMI, BM2. We then obtain the electrical shunt shown in [Fig.2].

[0064] In [Fig.6], different parameters are shown for designing the SHE electrical shunt of [Fig.2] before the drilling step (step e) above of the method according to the invention) of the assembly obtained after annealing: - D denotes the outer diameter of the PEL, DEL electrodes with 3.5mm < D < 50mm; - d denotes the inner diameter of the PEL, DEL electrodes with 1.5mm < d < 20mm and dmax = D / 1.75; - h denotes the thickness of the resistive element ER, with 1 mm < h < (D - d) / 2; - A denotes the angle of inclination given to the cavity with 1° < a < 90°, of preference A such that 30° < A <60°; and - L denotes the length of the electrical shunt with 5 mm < L < 100 mm.

[0065] The values ​​are adapted to the application.

[0066] Other geometries than that shown in [Fig.2] can be produced with the method according to the invention.

[0067] Thus, as an additional non-limiting example, it is possible to manufacture an electrical shunt SHE' of the “busbar” type as shown in [Fig.6].

[0068] In the present case, step a) starts with a solid substrate of parallelepiped shape, in which a cavity of the desired shape can be formed in step b), for example by machining. Here too, it would be possible to proceed differently to obtain the substrate with its non-through cavity. Step c) then repeats what was described previously, as do steps d), e) and f), regardless of the variants envisaged which are also applicable to this other geometry. At the end of step f), the electrical shunt SHE' is defined with its electrodes PEL', DEL' therefore provided with connection terminals BCE1', BCE2', the electrodes being connected to each other by the single resistive element ER'. Measuring terminals BMI', BM2' are then advantageously also produced, as can be seen in [Fig.6].

[0069] The electrical shunt SHE, SHE' obtained within the framework of the invention can in particular make it possible to measure the electrical consumption or the state of charge of batteries in the following fields: transport (car, aeronautics, rail, aerospace), metrology, industry and building. This electrical shunt finds more generally application to form any probe for measuring alternating current (AC) or direct current (DC) for electronics (10 to 500 A).

[0070] Example of embodiment: manufacturing of a hollow cylindrical electrical shunt

[0071] First of all, a solid, cylindrical, aluminum SBT substrate ([Fig.5a]) is provided, in accordance with step a) of the method according to the invention.

[0072] The substrate is then machined to define a non-through CVT cavity, in accordance with step b) of the method according to the invention, in this case of trapezoidal shape in section, over the entire periphery of the substrate. Furthermore, here, one of the ends of the substrate is also machined to define a holding rod TM useful for its handling during the manufacturing process ([Fig.5b]). Apart from the holding rod TM, the zones Z1, Z2 of the substrate located on either side of the CVT cavity are those which are intended to form the first electrode and the second electrode. These zones Z1, Z2 are connected to each other by a portion POR of substrate, in this case of cylindrical shape, intended to disappear subsequently in the manufacturing process.

[0073] Then, additive manufacturing of the resistive element ER is carried out in the CVT cavity, in accordance with step c) of the method according to the invention.

[0074] For this, the additive manufacturing process used is the process known as “Cold Spray” of the LPCS type (low pressure). We start with a powder mixture (compatible with the “Cold Spray” process) of manganin with a particle size of 5 to 50 μm and alumina with a particle size of 5 to 25 μm, the alumina representing 20% ​​by mass of the powder mixture. The process is carried out at a pressure of 8 bar and a temperature of 400 °C, in air. The substrate is continuously rotated at 60 rpm at a rotation speed of 30 mm / min. The coating is deposited with several successive layers, and for each layer the deposition is carried out in the form of helicoids. We take advantage of this additive manufacturing operation by "Cold Spray" to carry out a preliminary sandblasting of the surface of the substrate, in this case with alumina powder with a grain size of 250 microns. Sandblasting promotes the adhesion of the deposit made during additive manufacturing by "Cold Spray" and therefore ultimately the mechanical strength of the resistive element on the substrate, in other words ultimately on the electrodes ([Fig.5c]).

[0075] With additive manufacturing, the resistive element ER is dimensioned to obtain a defined value of its resistivity. This eliminates, compared to the prior art, a subsequent machining step (rework) of the resistive element to adapt it.

[0076] An annealing of the assembly obtained at this stage of the manufacturing is then carried out, in accordance with step d) of the method according to the invention. This annealing serves to restore the mechanical and electrical properties of the different materials. In this case, it is an annealing of 1h at 300°C.

[0077] Then, in accordance with step e) of the method according to the invention, a portion of the SBT substrate is removed to leave only the resistive element ER between the two zones Z1, Z2 of the substrate. In practice here, the substrate is pierced right through along its longitudinal axis AL. This operation removes the POR portion of the substrate which connected the two zones Z1, Z2. The desired hollow cylindrical shape is thus obtained.

[0078] In the present case, piercing the substrate from one side to the other allows step f) to be carried out at the same time in accordance with the method according to the invention. Indeed, this makes it possible to generate the connection terminals at the end of each of the zones Z1, Z2 to finally form the first electrode and the second electrode. Furthermore, in the context of this exemplary embodiment, the holding rod TM is also removed by this same operation.

[0079] The electrodes PEL, DEL and the resistive element ER are defined at this stage, as are the electrical connection terminals BCE1, BCE2 ([Fig.5d]).

[0080] It will then be possible, advantageously, to create measuring terminals BMI, BM2. To create these measuring terminals, a tapped hole can be made to fix a terminal there via a screw. A hole, for example a conical one, can also be made to house a spring-mounted contactor.

[0081] End of example.

Claims

Claims

1. Method for manufacturing an electric current sensor (SHE) comprising the following steps: a) providing a substrate (SBT) made of metal or metal alloy, b) producing a non-through cavity (CVT) in said substrate so that said cavity separates the substrate into two zones (Zl, Z2), c) producing, by additive manufacturing, a resistive element (ER) in said cavity (CVT), d) carrying out an annealing of the assembly thus obtained, e) removing a part of the substrate (SBT) to leave only the resistive element (ER) between the two zones (Zl, Z2) of the substrate, and f) defining, within each zone (Zl, Z2), a connection terminal (BCE1, BCE2) to obtain said electrodes (PEL, DEL).

2. A method of manufacturing an electric current sensor according to claim 1, wherein the substrate provided in step a) is made of Aluminum, Copper or a Copper-based alloy.

3. Method of manufacturing an electric current sensor according to one of the preceding claims, in which the cavity (CVT) produced in step b) is obtained by machining the substrate (SBT).

4. Method of manufacturing an electric current sensor according to one of the preceding claims, in which step c) is carried out by cold spraying, advantageously at a pressure of less than 15 bar.

5. A method of manufacturing an electric current sensor according to one of the preceding claims, wherein step d) is carried out at a temperature of between 400 and 600°C for a duration of between 5 and 15 minutes.

6. Method of manufacturing an electric current sensor according to one of the preceding claims, comprising an additional step of producing a measuring terminal (BMI, BM2) in each of the two electrodes (PEL, DEL).

7. Method of manufacturing an electric current sensor according to one of the preceding claims, in which the resistive element (ER) does not undergo any machining step, in particular to adapt the value of its resistivity.

8. A method of manufacturing an electric current sensor according to one of the preceding claims, wherein the substrate (SBT) provided in step a) is a solid cylinder.

9. Method of manufacturing an electric current sensor according to one of the preceding claims, in which the substrate (S) provided in step a) is a solid parallelepiped.

10. A method of manufacturing an electric current sensor according to one of the preceding claims, wherein said sensor is an electrical shunt.

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