Electrical transmission component, particularly for electric batteries

Abstract

Electricity transport component, in particular for ELECTRIC BATTERY The invention relates to an electricity transport component, in which the electricity transport component comprises a metallic surface, characterized in that said metallic surface is coated over its entire surface: - with an intermediate layer of polyolefin; and - with a coating layer in an electrically insulating composition comprising predominantly at least one polyamide in which the number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring material, the intermediate layer being positioned between the metallic surface of the electricity transport component and the coating layer and its preparation process, and its preparation process.

Description

Title of the invention: Electricity transport component, in particular for an electric battery. FIELD OF THE INVENTION

[0001] The present invention relates to an electricity transport component, and more particularly to an interconnection bar, colored in particular for an electric battery. TECHNICAL BACKGROUND

[0002] In the field of electric vehicles, connectors called interconnection bars (or bus bars) are present to circulate high-intensity current inside and outside the batteries. These bars must be covered by an insulating coating that is resistant to mechanical stress and aging.

[0003] Several methods exist for preparing busbars. The main one is the extrusion of the polymer composition around the central metal strip. Coating processes using powder, dipping or electro-spray can also be used. These structures are then cut and bent (at room temperature) to adopt the shape required by the vehicle layout.

[0004] For safety reasons, these bars must also have a distinctive color, representative of the current flowing in the bar. It is therefore essential that this color remains stable over time, despite the temperatures to which the bar may be subjected. Indeed, external conditions, proximity to the engine, self-heating during current flow, in particular during battery charging are factors that can affect the color of the coating over time. If the color changes over time, doubt may remain about the voltage of the electric current flowing in the bar, which could cause accidents during servicing or repair of the engine, for example. It is therefore essential that the color remains stable despite the drastic conditions of its environment.

[0005] The technical problem related to the busbar application for batteries consists of forming a thin layer of polymer, the coloring of which does not change over time, while maintaining a high level of flexibility to accommodate the deformation of the busbars. When bending, a material that is too rigid forms cracks on the external face and buckling on the internal face, which is visualized by 'waves' or 'bulges', phenomena which are prohibitive for the application.

[0006] The behavior at the plasticity threshold of the material is therefore crucial. Low stresses at the threshold and a large elongation at the threshold are sought. The levels of The deformation of these coatings remains low, but the material must still have an elongation at break > 50%, preferably greater than 100%, even more advantageously greater than 200%. Good abrasion resistance is also necessary for this application.

[0007] In addition, depending on the position of these parts within the engine, it may be advantageous for these compositions to be resistant to de-icing salt.

[0008] The coating must also act as an electrical insulator, which is reflected in properties such as breakdown voltage, dielectric strength and comparative tracking index (CTI) > 600V. This insulation must be maintained during accelerated thermal aging of up to 150°C.

[0009] It is also important that the colored layer adheres correctly to the metal surface of the component.

[0010] Finally, the rheological properties of the alloy must be adapted to the extrusion of thin polymer layers of the order of 0.5 mm.

[0011] Furthermore, the prior art does not provide information on the combinations to be made within the formulation to simultaneously achieve flexibility and color stability for the battery busbar application. Summary of the invention

[0012] The invention relates to an electricity transmission component, in which the electricity transmission component comprises a metallic surface, characterized in that said metallic surface is coated over its entire surface: - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising mainly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring material, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer.

[0013] The invention also relates to a method for preparing an electricity transport component as defined above comprising: - a step of coating the entire metal surface of the electricity transport component with an intermediate layer of polyolefin; then - a step of coating the intermediate polyolefin layer with a coating composition.

[0014] It has been observed that the color of the composition according to the invention remains stable even after aging at high temperature. It has also been observed that the electrical insulation properties have been preserved. Furthermore, the composition according to the invention has good mechanical properties: the elongation properties at the rupture, impact resistance, and the resistance of the polymer layer when bending the metal bar are very satisfactory.

[0015] Other advantageous characteristics of the method according to the invention are specified below: - the component is an interconnection bar, - the metal surface is made of copper, copper alloy, aluminum or aluminum alloy, - the polyolefin is chosen from: - non-functionalized polyolefins (B2) in particular homopolymer or copolymer of alpha olefins or diolefins, such as for example, ethylene, propylene, butene-1, octene-1, butadiene, preferably homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene; homopolymers or copolymers of propylene; ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM);- styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers, copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (for example methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer being able to reach 40% by weight; ; - functionalized polyolefins (Bl) chosen from a polymer of alpha olefins having reactive units of the acid, anhydride, or epoxy function type, for example polyolefins (B2) grafted or co- or terpolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid or even by carboxylic acid anhydrides such as maleic anhydride; - their mixtures. - the intermediate polyolefin layer has a thickness of between 10 and 1000 pm, preferably between 30 and 500 pm, advantageously between 50 and 300 pm, - the coloring matter content ranges from 0.5 to 10% by weight, preferably from 1 to 5% by weight relative to the total weight of the composition, - the polyamide(s) have an inherent viscosity measured according to ISO 307:2007 greater than 1.1, - the polyamide(s) have a fusion enthalpy measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly greater than 20 J / g, - the polyamide(s) have a crystallization temperature measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly lower than 180°C, - the polyamide is chosen from a PAU, PA12, PA1010, PA 1012, PA 610, PA 612, PA 613, PA 912, PA 516, PA 6 / 11, PA 6 / 12, PA 11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture, more particularly PAU, PA 12, PA 1010, PA 1012, even more preferably PA11 or PA 12, preferably PAU, - the polyamide(s) of the composition of the coating layer have a difference, expressed as an absolute value, between its total acidity and its total basicity of less than 70 and a basicity of the total polyamide(s) of less than 60 peq / g, - the polyamide(s) of the composition of the coating layer have a total acidity of less than 60 peq / g, - according to the method, the coating step of the intermediate layer is carried out by extrusion, - according to the method, the step of coating the intermediate layer is carried out by depositing a powder of said coating composition and then melting the powder. DETAILED DESCRIPTION

[0016] Other characteristics, aspects, objects and advantages of the present invention will appear even more clearly on reading the description which follows.

[0017] The nomenclature used to define polyamides is described in the standard ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art. Thus, PA11 means that it is obtained by polycondensation of amino-11-undecanoic acid. PA12 is obtained by polycondensation of lauryllactam. PA1010 is obtained by polycondensation of decanediamine (10) and decanedioic acid (10). PA1012 is obtained by polycondensation of decanediamine (10) and dodecanedioic acid (12).

[0018] It is further specified that the expressions "between... and..." and "from... to..." used in the present description must be understood as including each of the limits mentioned.

[0019] The word "polyamide" covers both homopolyamides and copolyamides.

[0020] The invention is now described in more detail and in a non-limiting manner in the following description. Electricity transmission component

[0021] The subject of the invention is an electricity transmission component, preferably an interconnection bar, in which the electricity transmission component comprises a metal surface, characterized in that said metal surface is coated over its entire surface: - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising mainly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring material, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer.

[0022] Preferably, the electricity transmission component is an interconnection bar. In this embodiment, the invention then relates to an interconnection bar comprising: - a metal bar; - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising mainly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring matter, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer.

[0023] The electricity transmission component is preferably a high voltage electricity transmission component. High voltage means voltages between 400 and 1000 V.

[0024] Preferably, the electricity transmission component is an interconnection bar. In this embodiment, the invention then relates to an interconnection bar comprising: - a metal bar; - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising mainly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring matter, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer.

[0025] The electricity transmission component can be of any type. It is mainly a high voltage electricity transmission component. This component can be in the form of a metal cable or comprising metal fibers, for example braided, or thin superimposed metal sheets or metal bars such as those usually used in interconnection bars.

[0026] Preferably, the electricity transport component comprises a metal surface metal, preferably copper, copper alloy, aluminum or aluminum alloy, preferably copper or aluminum, preferably copper.

[0027] In one embodiment, the electricity transport component is an interconnection bar comprising a metal bar, said metal bar preferably being made of copper, copper alloy, aluminum or aluminum alloy, preferably copper or aluminum, preferably copper.

[0028] Polyolefin intermediate layer

[0029] The intermediate layer is a polyolefin layer. Preferably, this layer completely covers the metal surface of the electricity transport component.

[0030] The polyolefin is preferably chosen from functionalized, non-functionalized polyolefins and a mixture of the two.

[0031] For simplicity, the polyolefin has been designated (B) and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) have been described below.

[0032] A non-functionalized polyolefin (B2) is conventionally a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, butene-1, octene-1, butadiene. By way of example, mention may be made of: - homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene, - homopolymers or copolymers of propylene, - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM), - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers, - copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (for example methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer being able to reach 40% by weight.

[0033] The functionalized polyolefin (B1) may be a polymer of alpha olefins having reactive units (the functionalities); such reactive units are acid, anhydride, or epoxy functions. By way of example, mention may be made of the preceding polyolefins (B2) grafted or co- or terpolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid (the latter being able to be neutralized totally or partially by metals such as Zn, etc.) or even by anhydrides of carboxylic acids such as maleic anhydride. A functionalized polyolefin is for example a PE / EPR blend, the weight ratio of which can vary widely, for example between 40 / 60 and 90 / 10, said blend being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate for example of 0.01 to 5% by weight.

[0034] The functionalized polyolefin (Bl) can be chosen from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting rate is for example from 0.01 to 5% by weight: - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing for example 35 to 80% by weight of ethylene; - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM); - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers; - ethylene and vinyl acetate (EVA) copolymers, containing up to 40% by weight of vinyl acetate; - ethylene and alkyl (meth)acrylate copolymers, containing up to 40% by weight of alkyl (meth)acrylate; - ethylene vinyl acetate (EVA) and alkyl (meth)acrylate copolymers, containing up to 40% by weight of comonomers.

[0035] The functionalized polyolefin (Bl) can also be chosen from ethylene / propylene copolymers with a majority of propylene grafted with maleic anhydride then condensed with mono-amine polyamide (or a polyamide oligomer) (products described in EP-A-0342066).

[0036] The functionalized polyolefin (Bl) may also be a co- or terpolymer of at least the following units: (1) ethylene, (2) alkyl (meth)acrylate or saturated carboxylic acid vinyl ester and (3) anhydride such as maleic anhydride or (meth)acrylic acid or epoxy such as glycidyl (meth)acrylate.

[0037] As examples of functionalized polyolefins of the latter type, mention may be made of the following copolymers, where ethylene preferably represents at least 60% by weight and where the ter monomer (the function) represents, for example, from 0.1 to 10% by weight of the copolymer: - ethylene / alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymers; - ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymers; - ethylene / vinyl acetate or alkyl (meth)acrylate / acid copolymers (meth)acrylic or maleic anhydride or glycidyl methacrylate.

[0038] In the above copolymers, (meth)acrylic acid can be salified with Zn or Li.

[0039] The term "alkyl (meth)acrylate" in (B1) or (B2) denotes C1 to C8 alkyl methacrylates and acrylates, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0040] Furthermore, the aforementioned polyolefins (B 1) can also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the aforementioned polyolefins with a difunctional reagent such as diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins capable of reacting with each other.

[0041] The above-mentioned copolymers, (B1) and (B2), can be copolymerized in a random or block manner and have a linear or branched structure.

[0042] The molecular weight, the MFI index, the density of these polyolefins can also vary to a large extent, which a person skilled in the art will appreciate. MFI, abbreviation of Melt Flow Index, is the melt flow index. It is measured according to the ASTM 1238 standard.

[0043] Advantageously, the non-functionalized polyolefins (B2) are chosen from homopolymers or copolymers of polypropylene and any homopolymer of ethylene or copolymer of ethylene and a comonomer of higher alpha olefin type such as butene, hexene, octene or 4-methyl-1-pentene. Examples that may be mentioned are PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE, styrene / ethylene-butene / styrene (SEBS) block copolymers, styrene / ethylene-propylene / styrene (SEPS). These polyethylenes are known to those skilled in the art as being produced according to a “radical” process, according to a “Ziegler” type catalysis or, more recently, according to a so-called “metallocene” catalysis.

[0044] Advantageously, the functionalized polyolefins (B1) are chosen from any polymer comprising alpha olefinic units and units carrying polar reactive functions such as epoxy, carboxylic acid or carboxylic acid anhydride functions. Examples of such polymers include terpolymers of ethylene, alkyl acrylate and maleic anhydride or glycidyl methacrylate such as Lotader® (SK functional polymer) or polyolefins grafted with maleic anhydride such as Orevac® (SK functional polymer) as well as terpolymers of ethylene, alkyl acrylate and (meth)acrylic acid. Homopolymers or copolymers of polypropylene grafted with a carboxylic acid anhydride and then condensed with polyamides or mono-amino polyamide oligomers.

[0045] In one embodiment, the polyolefin is functionalized.

[0046] Advantageously, the non-functionalized polyolefin is chosen from a polyethylene and a polypropylene, in particular a polyethylene, in particular a low density polyethylene (LDPE).

[0047] The polyolefin layer preferably has a thickness of between 10 and 1000 μm, preferably between 30 and 500 μm, advantageously between 50 and 300 μm.

[0048] Particularly advantageously, the polyolefin layer makes it possible to maintain a stable color over time even at high temperatures while allowing good adhesion of the coating layer and mechanical resistance.

[0049] Any other organic polymer could be used to replace the polyolefin layer according to the invention.

[0050] Coating layer

[0051] The electricity transport component according to the invention, preferably an interconnection bar, comprises a coating layer made of an electrically insulating composition mainly comprising at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring material.

[0052] By electrically insulating, we mean, in the sense of the present invention, a material having a dielectric strength greater than 10 kV / mm measured on a 1 mm thick plate on a sample conditioned for 14 days at 25°C at 50% relative humidity according to standard IEC 60243-1:2013.

[0053] Preferably, the thickness of the coating layer is from 0.1 mm to 2 mm, in particular from 0.2 mm to 1 mm, in particular from 0.3 mm to 0.8 mm, more particularly from 0.4 mm to 0.6 mm, while maintaining a high level of flexibility to accommodate the deformation of the electricity transport component. A material that is too rigid forms cracks or “waves” which are prohibitive for the application.

[0054] Composition of the coating layer

[0055] The composition forming the coating layer mainly comprises at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring material.

[0056] For the purposes of the present invention, the term “predominantly” means that the composition comprises at least one polyamide in a content greater than 50% by weight relative to the total weight of the composition. This or these polyamides constitute the matrix of the composition.

[0057] Preferably, the composition of the coating layer comprises between 60 and 98% by weight of at least one polyamide relative to the total weight of the composition, preferably between 70% and 95%.

[0058] Preferably, the composition of the coating layer comprises between 0.5 and 10% by weight, preferably between 1 and 5% by weight of coloring matter.

[0059] Preferably, the composition of the coating layer comprises between 60 and 98% by weight, preferably between 70 and 95% by weight, of polyamide and between 0.5 and 10% by weight, preferably between 1 and 5% by weight of coloring matter.

[0060] In the case of a homopolyamide of PA-XY type, with X designating a unit obtained from a diamine and Y designating a unit obtained from a diacid, the number of carbon atoms per nitrogen atom is the average of the numbers of carbon atoms present in the unit derived from the diamine X and in the unit derived from the diacid Y. Thus PA6.12 is a PA with 9 carbon atoms per nitrogen atom, in other words a C9 PA. PA6.13 is C9.5. In the case of copolyamides, for example of structure XaYa / XbYb, the number of carbon atoms per nitrogen atom is calculated according to the same principle. The calculation is carried out in molar proportion to the different amide units, i.e. the XaYa and XbYb units.

[0061] The majority polyamide present in the composition of the coating layer has a number of carbon atoms per nitrogen atom greater than 6.5, preferably greater than 8.

[0062] For the purposes of the present invention, the term “majority” means that the composition comprises at least one polyamide in a content greater than 50% by weight relative to the total weight of the composition. In other words, the composition may comprise a mixture of polyamides having a number of carbon atoms per nitrogen atom greater than 6.5. This mixture must be majority, that is to say that it must represent at least 50% by weight relative to the total weight of the composition.

[0063] Preferably, the composition comprises between 60 and 98% by weight of at least one polyamide relative to the total weight of the composition, preferably between 70% and 95%.

[0064] In other words, the presence of other polyamides is not excluded. However, it is important that the highly carbon-based polyamides are in the majority within the composition.

[0065] The polyamide present in the composition of the coating layer of the component according to the invention is obtained by polycondensation of at least one unit chosen from a C6 to C18 alpha, omega-aminocarboxylic acid, a C5 to C12 lactam and a (Ca diamine) (Cb diacid) unit, with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0066] The polyamide can be obtained by polycondensation of at least one lactam chosen from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam, pelar- golactam, decanolactam, undecanolactam, and lauryllactam.

[0067] The polyamide can also be obtained by polycondensation of at least one amino acid chosen from 9-aminononanoic acid, 10-aminodecanoic acid (noted 10), amino-11-undecanoic acid (noted 11), amino-12-dodecanoic acid (noted 12).

[0068] The polyamide can be obtained by polycondensation of at least one unit corresponding to the formula (Ca diamine). (Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0069] The unit (diamine in Ca) can be aliphatic, cycloaliphatic or aromatic. It can be chosen from butanediamine (a=4), pentanediamine (a=5), hexanediamine (a=6), heptanediamine (a=7), octanediamine (a=8), nona-nediamine (a=9), decanediamine (a= 10), undecanediamine (a= 11), dodeca-nediamine (a= 12), tridecanediamine (a= 13), tetradecanediamine (a= 14), hexadecanediamine (a= 16), octadecanediamine (a= 18), m-xylylenediamine (denoted MXD), methylpentamethylenediamine (denoted MPMD), bis(aminomethyl)cyclohexane (denoted BAC), meta-xylylenediamine (MXD, CAS No.: 1477-55-0) and para-xylylenediamine (PXD, CAS No.: 539-48-0).

[0070] Advantageously, said at least one diamine X in C6 to C12, is in particular chosen from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0071] Advantageously, the diamine X used is C10 to C12, in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0072] The unit (Cb diacid) can be aliphatic, cycloaliphatic or aromatic. It can be chosen from succinic acid (b=4), pentanedioic acid (b=5), adipic acid (b=6), heptanedioic acid (b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid (b= 10), undecanedioic acid (b= 11), do-decanedioic acid (b= 12), brassylic acid (b= 13), tetradecanedioic acid (b= 14), hexadecanedioic acid (b= 16), octadecanedioic acid (b= 18) and diacids obtained from fatty acids, terephthalic acid (denoted T).

[0073] Advantageously, said unit (Cb diacid) is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0074] Advantageously, the polyamide present in the composition of the re- clothing of the component according to the invention is aliphatic.

[0075] Advantageously, the polyamide is chosen from PAU, PA12, PA1010, PA 1012, PA 610, PA 612, PA 613, PA 912, PA 516, PA 6 / 11, PA 6 / 12, PA 11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture.

[0076] Preferably, the composition only comprises polyamides having a number of carbon atoms per nitrogen atom greater than 6.5. More particularly, the composition only comprises polyamides having a number of carbon atoms per nitrogen atom greater than 8.

[0077] According to a preferred embodiment, the polyamide is a homopolyamide. This homopolyamide can be obtained by the polycondensation of a lactam, an amino acid or a (Ca diamine) (Cb diacid) unit, with Ca and Cb being as defined above.

[0078] More particularly, the composition mainly comprises PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA12, preferably PAU.

[0079] PA11 has the advantage of being manufactured from raw materials of plant origin. Plant materials can be grown in large quantities, depending on demand, over most of the globe and can be bio-sourced. A bio-sourced raw material is a natural resource, animal or plant, whose stock can be replenished over a short period on a human scale. In particular, this stock must be able to be renewed as quickly as it is consumed.

[0080] The basic raw material of PA11 is castor oil, extracted from the plant of the same name (the common castor oil plant), from castor beans. PA11 is obtained by polycondensation of amino-11-undecanoic acid. Total acidity and total basicity

[0081] Preferably, the polyamide(s) present in the composition of the coating layer of the component according to the invention have a difference, expressed as an absolute value, between its total acidity and its total basicity strictly less than 70, preferably less than 50, ideally less than 30.

[0082] By difference, expressed as an absolute value, is meant, within the meaning of the present invention, the result of the subtraction of the values ​​of the total acidity of the polyamide(s) and the total basicity of the polyamide(s), without taking into account the sign.

[0083] When the composition comprises a mixture of polyamides, the acidity and basicity are measured on the mixture of polyamides. The difference is therefore expressed for the mixture of polyamides.

[0084] Preferably, the polyamide(s) present in the composition of the component according to the invention also have a total basicity strictly less than 60 peq / g, preferably less than 50 peq / g, and ideally less than 40 peq / g.

[0085] Preferably, the polyamide(s) present in the composition of the component according to the invention also have a total acidity strictly less than 60 peq / g, preferably less than 50 peq / g, and ideally less than 40 peq / g.

[0086] Acidity and basicity are measured by potentiometry.

[0087] The acidity is measured according to the following method. A sample of polyamide is dissolved in benzyl alcohol. Then, this sample is assayed by potentiometry with a 0.02N tetrabutylammonium hydroxide solution.

[0088] The basicity is measured according to the following method. A sample of polyamide is dissolved in metacresol. Then, this sample is assayed by potentiometry with a 0.02N perchloric acid solution.

[0089] According to one embodiment of the invention, the polyamide(s) have a total basicity strictly less than 60 peq / g and a total acidity strictly less than 60 peq / g and a difference, expressed as an absolute value, between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0090] According to a preferred embodiment, the composition mainly comprises PAU, PA 12, PA 1010 or PA 1012 and their mixture, this or these polyamides having a total basicity of less than 60 peq / g and a difference, expressed in absolute value, between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0091] According to a preferred embodiment, the composition mainly comprises PA11 or PA12, having a total basicity of less than 50 peq / g and a total acidity of less than 60 peq / g and a difference, expressed as an absolute value, between its total acidity and its total basicity strictly less than 30.

[0092] Preferably, the polyamide(s) present in the composition do not comprise a chain limiter. Inherent viscosity

[0093] Preferably, the polyamide(s) of the composition of the coating layer have an inherent viscosity measured according to ISO 307:2007 of greater than 1.1, and preferably of greater than 1.2.

[0094] The measurement is carried out at 20°C on a 75 mg sample at a concentration of 0.5% (m / m) in m-cresol.

[0095] When the composition comprises a mixture of polyamides, the viscosity is measured on the mixture of polyamides. Enthalpy of fusion

[0096] Preferably, the polyamide(s) of the composition of the coating layer have a fusion enthalpy greater than 20 J / g, preferably greater than 30 J / g and ideally greater than 40 J / g.

[0097] The enthalpy of fusion is measured by DSC (differential scanning calorimetry measurement) according to ISO 11357-3, 2013 (2nd DSC heating at 20°C / min according to ISO 11357).

[0098] When the composition comprises a mixture of polyamides, the enthalpy of fusion is measured on the mixture of polyamides. Crystallization temperature

[0099] Preferably, the polyamide(s) of the composition of the coating layer have a crystallization temperature of less than 180°C, preferably less than 160°C.

[0100] The crystallization temperature is measured by DSC (differential scanning calorimetry) according to ISO 11357-3, 2013 (2nd DSC heating at 20°C / min according to ISO 11357).

[0101] When the composition comprises a mixture of polyamides, the crystallization temperature is measured on the mixture of polyamides.

[0102] The coloring matter

[0103] The composition of the coating layer of the component according to the invention comprises at least one coloring material. The coloring material may be a dye or a pigment, in other words, water-soluble dyes or water-insoluble pigments according to the conditions defined below.

[0104] The dye may be of any type known to those skilled in the art. Preferably, the dye according to the invention is selected from the group consisting of azo dyes, anthraquinone dyes, indigo-derived dyes, triarylmethane dyes, chlorine dyes and polymethine dyes.

[0105] By "pigment" is meant all pigments providing color to a polymer composition. Their solubility in water at 25°C and at atmospheric pressure (760 mmHg) is less than 0.05% by weight, and preferably less than 0.01%. The pigments which can be used are in particular chosen from organic and / or mineral pigments known in the art, in particular those described in the Kirk-Othmer encyclopedia of chemical technology and in the Ullmann encyclopedia of industrial chemistry.

[0106] The pigments may be of natural origin or not. These pigments may be in the form of powder or pigment paste. They may be coated or uncoated. The pigments may, for example, be chosen from mineral pigments, organic pigments and their mixtures.

[0107] By mineral pigment is meant any pigment which meets the definition of the Ullmann encyclopedia in the inorganic pigment chapter. Among the mineral pigments useful in the present invention, mention may be made of ochres such as red ochre. (clay (especially kaolinite) and iron hydroxide (e.g. hematite), brown ochre (clay (especially kaolinite) and limonite), yellow ochre (clay (especially kaolinite) and goethite); titanium dioxide, possibly surface-treated; zirconium or cerium oxides; zinc, iron (black, yellow or red), or chromium oxides; manganese violet, ultramarine blue, chromium hydrate and ferric blue; metal powders such as aluminium powder, copper powder.

[0108] Mention may also be made of alkaline earth metal carbonates (such as calcium, magnesium), silicon dioxide, quartz, as well as any other compound used as an inert filler in cosmetic compositions, provided that these compounds provide color or white to the composition under the conditions in which they are used.

[0109] The pigment may be an organic pigment. By "organic pigment" is meant any pigment that meets the definition of the Ullmann encyclopedia in the organic pigment chapter.

[0110] The organic pigment may in particular be chosen from nitroso, nitro, azo, xanthene, pyrene, quinoline, quinoline, anthraquinone, triphenylmethane, fluorane, phthalocyanine, metal complex type compounds, isoindolinone, isoindoline, qui-nacridone, perinone, perylene, diketopyrrolopyrrole, indigo, thioindigo, dioxazine, triphenylmethane, quinophthalone.

[0111] In particular, the white or colored organic pigments may be chosen from carmine, carbon black, aniline black, azo yellow, quinacridone, phthalocyanine blue, the blue pigments codified in the Color Index under the references Cl 42090, 69800, 69825, 74100, 74160, the yellow pigments codified in the Color Index under the references Cl 11680, 11710, 19140, 20040, 21100, 21108, 47000, 47005, the green pigments codified in the Color Index under the references Cl 61565, 61570, 74260, the orange pigments codified in the Color Index under the references Cl 11725, 45370, 71105, the red pigments codified in the Color Index under the references CI 12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, 75470.

[0112] Advantageously, the pigment is chosen from the pigments CI Pigment Orange 82 [CAS No. 2170864-77-2] and CI Pigment Yellow 216 [CAS No. 817181-98-9]. Pigment Orange 82 can be obtained, for example, under the name Sicopal® Orange K2430 from Sun Chemical, Ludwigshafen, Germany. Pigment Yellow 216 can be obtained, for example, under the name Orange 10P340 from Shepherd, Gent, Belgium.

[0113] Among the colorants, mention may be made of carminic acid. Mention may also be made of the colorants known under the following names: D & C Red 21 (CI 45 380), D & C Orange 5 (CI 45 370), D & C Red 27 (CI 45 410), D & C Orange 10 (CI 45 425), D & C Red 3 (CI 45 430), D & C Red 4 (CI 15 510), D & C Red 33 (CI 17 200), D & C Yellow 5 (CI 19 140), D & C Yellow 6 (CI 15 985), D & C Green (CI 61 570), D & C Yellow 1 O (CI 77 002), D & C Green 3 (CI 42 053), D & C Bine 1 (CI 42 090).

[0114] The coloring material may be selected from the group consisting of titanium dioxide, carbon black, cobalt oxide, nickel titanate, molybdenum disulfide, aluminum flakes, iron oxide, zinc oxide, organic pigments, such as phthalocyanine and anthraquinone derivatives, and zinc phosphate.

[0115] Preferably, the composition of the coating layer comprises at least one coloring material leading to an orange color.

[0116] Preferably, the chosen colorant(s) result in a RAL 2003 color composition, i.e. have the following L*a*b* values: L* = 66.0; a* = 41.2 and b* = 52.4.

[0117] Advantageously, the coloring material is a mixture of at least two pigments. More preferably, the coloring material comprises titanium dioxide, tin oxide, zinc oxide and their mixture. Even more preferably, the coloring material comprises titanium dioxide, tin oxide, zinc oxide and at least two additional pigments, preferably leading to the orange color.

[0118] Preferably, the coloring matter content in the composition is between 0.5 and 10%, advantageously between 1 and 5% by weight relative to the total weight of the composition.

[0119] Preferably, the composition of the coating layer comprises between 60 and 98% by weight, preferably between 70 and 95% by weight, of polyamide and between 0.5 and 10% by weight, preferably between 1 and 5% by weight of coloring matter.

[0120] Additives

[0121] Preferably, the composition according to the invention comprises at least one additive chosen from flame retardants, UV protective agents, UV stabilizers, heat stabilizers, lubricants, fluidity improving agents, flowability improving agents, film-forming agents, fillers, film-forming auxiliaries, gums, preservatives, antibacterial agents and mixtures thereof. Preferably, the composition according to the invention does not comprise metal-based additives, so as to avoid any harmful interaction between the metal surface to be covered and these additives potentially present within the composition according to the invention.

[0122] Antioxidants

[0123] Preferably, the composition of the coating layer comprises at least one antioxidant.

[0124] For example, the stabilizer may be an organic stabilizer or more generally a combination of organic stabilizers, such as a phenol-type antioxidant (for example of the type of irganox® 245 or 1098 or 1010 from the company Ciba-BASF), a phosphite-type antioxidant (for example irgafos® 126 or Irgafos® 168 from the company Ciba-BASF) and possibly other stabilizers such as a HALS, which means Hindered Amine Light Stabilizer or hindered amine light stabilizer (for example Tinuvin® 770 from the company Ciba-BASF), an anti-UV agent (for example Tinuvin® 312 from the company Ciba), a phosphorus-based stabilizer. It is also possible to use amine-type antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0125] According to a preferred embodiment, the electricity transport component comprises a metal surface, characterized in that said metal surface is coated over its entire surface: - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising mainly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 8 and at least one coloring matter, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer, the metal surface being made of copper.

[0126] According to an even more preferred embodiment, the electricity transport component comprises a metal surface, characterized in that said metal surface is coated over its entire surface: - an intermediate layer of polyolefin; and - a coating layer made of an electrically insulating composition comprising -predominantly at least one polyamide, the polyamide(s) having: - a difference, expressed in absolute value, between the total acidity and the total basicity less than 70 and - a total basicity of the polyamide(s) of less than 60 peq / g, and the composition comprising predominantly at least one polyamide having a number of carbon atoms per nitrogen atom of greater than 6.5 and at least one coloring matter, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer, the metal surface being copper.

[0127] Use of the electricity transmission component

[0128] In one embodiment, said electricity transport component, preferably said interconnection bar, is located inside and / or outside electric batteries, in particular vehicle electric batteries, in particular motor vehicles. It may for example be immersed in a coolant.

[0129] Process for preparing the electricity transmission component

[0130] According to yet another aspect, the present invention relates to a method for preparing an electricity transport component, preferably an interconnection bar, in particular an electric battery, comprising: - a step of coating the entire metal surface of the electricity transport component with an intermediate layer of polyolefin as defined above; - a step of coating the intermediate polyolefin layer with a coating composition as defined above.

[0131] Preferably, the step of covering the intermediate polyolefin layer with a coating composition as defined above can be carried out by extrusion of the composition or by depositing a powder of said coating composition and then melting the powder.

[0132] Preferably, the preparation process comprises an extrusion step and does not comprise a powder coating step.

[0133] The method according to the invention may consist of a co-extrusion of the polyolefin layer and the coating layer according to the invention.

[0134] Preferably, the invention relates to a method for preparing an interconnection bar according to the invention, in particular an electric battery, comprising: - a step of coating the entire metal surface of the bar with an intermediate layer of polyolefin as defined above; - a step of coating the intermediate polyolefin layer with a coating composition as defined above.

[0135] It is possible for the metal surface of the electricity transport component, preferably the metal bar of the interconnection bar, to undergo a pretreatment step before being covered by the intermediate polyolefin layer. The method may comprise, for example, a step of degreasing the metal surface and / or a singeing step and / or a preheating step.

[0136] All the characteristics defined above are valid for the method.

[0137] Other aims and advantages of the present invention will appear on reading the following examples given without limitation. EXAMPLES Preparation of coating compositions

[0138] Coating compositions according to the invention were prepared using the following compounds.

[0139] The polyamide according to the invention, denoted PA11, is prepared according to the following process. 43.00 kg of 11-aminoundecanoic acid, 30 g of phosphoric acid and 6.0 kg of deionized water are loaded into an autoclave and heated to 250°C while maintaining autogenous pressure for 30 min. As soon as the monomer melts, the medium is stirred at 40 rpm for the entire duration of the synthesis. A progressive expansion is applied for 2 hours up to 1 bar while raising the temperature to 255°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 30 minutes while maintaining the temperature at 255°C. Finally, stirring is stopped and the melt extruded under a pressure of 6 bars. The rod is cooled in a water bath and then granulated.

[0140] The polyamide according to the invention PA12 is prepared according to the following process. 25.00 kg of laurolactam and 2.20 kg of deionized water are loaded into an autoclave and heated to 290°C under a pressure of 32 bar for 5 hours. As soon as the monomer melts, the medium is stirred at 40 revolutions per minute for the entire duration of the synthesis. A progressive expansion is applied for 8 hours up to 8 bars while maintaining the temperature at 290°C. Then an expansion in one hour up to 0.2 bar is applied while gradually lowering the temperature to 265°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 15 minutes while maintaining the temperature at 265°C. Finally, a vacuum is applied to bring the pressure to 0.3 bar for 15 minutes. Finally, the stirring is stopped and the melt extruded under a pressure of 10 bars. The rod is cooled in a water bath and then granulated.

[0141] The polyamides tested have the characteristics indicated in Table 1: [Tables 1] PAU PA 12 Total basicity (peq / g) 48 32 Total acidity (peq / g) 57 35 A 9 3 Viscosity 1.42 1.58 AHf(J / g) 65 67 TcnstCQ 152 153 Table 1 Measurement of total basicity

[0142] The basicity is measured according to the following method. 1g of polyamide is dissolved in 80 mL of hot metacresol. The sample is then cooled. Then, it is dosed by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, by a 0.02N perchloric acid solution in acetic acid. The potential curve as a function of volume gives a jump with an equivalent volume from which the total basicity is calculated, using the following formula:

[0143] [Math.l] „ / \ Veq x[HCIO4] Total basicity i meq / gi = —Hîï---- in which Veq denotes the equivalent volume obtained by potentiometric dosing, [HC1O4] denotes the concentration of the perchloric acid solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1g. Total acidity measurement

[0144] The acidity is measured according to the following method. 1g of polyamide is dissolved in 80 mL of hot benzyl alcohol. The sample is then cooled. Then, it is dosed by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, by a 0.02N tetrabutylammonium hydroxide solution. The potential curve as a function of volume gives a jump with an equivalent volume from which the total acidity is calculated using the following formula:

[0145] [Math.2] Total acidity (meq g) = in which Veq denotes the equivalent volume obtained by potentiometric dosing, [TBAOH] denotes the concentration of the tetrabutylammonium hydroxide solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1g.

[0146] Calculation of the difference between total acidity and basicity

[0147] The difference is obtained by calculating the subtraction of the values ​​between the total acidity and the total basicity, in absolute value, that is to say without taking into account the sign.

[0148] For example, for PA 11 a:

[0149] [Math.3] d= |57-48| =9 Measurement of inherent viscosity

[0150] The measurement is carried out at 20°C on a 75 mg sample at a concentration of 0.5% (m / m) in m-cresol. The inherent viscosity is calculated according to the formula next:

[0151] [Math 4]

[0152] Inherent viscosity = ln(ts / t0) x 1 / C, with C = m / px 100, in which ts is the flow time of the solution, to is the flow time of the solvent, m is the mass of the sample whose viscosity is determined and p is the mass of the solvent. This measurement corresponds to the ISO 307:2007 standard except that the measurement temperature is 20°C instead of 25°C. Measurement of the enthalpy of fusion

[0153] The enthalpy of fusion is determined according to ISO 11357-3:2013 by DSC during the second heating. Measurement of crystallization temperature

[0154] The crystallization temperature is determined according to ISO 11357-3:2013 by differential scanning calorimetry (DSC) during cooling at a rate of 20°C / min.

[0155] The tested compositions also include the following compounds:

[0156] A phenolic-type primary antioxidant sold under the trade name Irganox 245® by BASF (CAS No.: 36443-68-2).

[0157] A phosphite-type secondary antioxidant sold under the trade name Irgafos 168® by BASF (CAS No.: 31570-04-4).

[0158] A mixture of pigments sold under the trade name 338160 ORA LLDPE AO Smartbatch by Avient comprising 28% pigments.

[0159] The following compositions are prepared by melt mixing the various raw materials in a 26 mm diameter co-rotating twin-screw extruder. The products are extruded at a flow rate of 16 kg / h, at a temperature of 250°C and with a screw speed of 250 rpm. At the machine outlet, the products are cooled by passing through a water tank and then granulated. These products are finally dried under vacuum for 8 hours at 80°C. The formulations of the compositions are shown in Table 2 below: [Tables 2] AB PAU 95 - PA12 - 95 Irganox 245 0.8 0.8 Irgafos 168 0.2 0.2 Colorant 4 4 Table 2 Sample preparation

[0160] From these compositions, plates (60x60xlmm) and ISO 527-1A dumbbells are injected at a temperature of 260°C. Measurement of mechanical properties

[0161] The tensile mechanical properties are measured according to ISO 527-1:2012 on dry samples. The machine used is an Instron 5966 with a crosshead speed of 50 mm / min.

[0162] The results are presented in Table 3. [Tables 3] AB Threshold stress (MPa) 41 45 Table 3

[0163] Measurement of colorimetric and electrical properties:

[0164] The dielectric strength is measured according to IEC 60243-1:2013 on a 1 mm thick plate at 25°C.

[0165] The colorimetric properties of the samples are measured in the CIELab system, as defined in ISO 11664-4: 2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0166] In this L* a* b* system, L* represents brightness, a* indicates the green / red color axis and b* the blue / yellow color axis. The higher the value of L*, the lighter or less intense the color. Conversely, the lower the value of L*, the darker or very intense the color. The higher the value of a*, the redder the shade and the higher the value of b*, the more yellow the shade.

[0167] The results are presented in Table 4 below: [Tables 4] AB Dielectric strength (kV / mm) 27 28 L* 62.5 62.1 a* 33.6 33.4 b* 36.5 37.7 Table 4

[0168] Preparation of coated metal bars

[0169] The following intermediate layers are used:

[0170] Intermediate layer 1: 200 μm thick film of functionalized polyethylene sold under the trade name Orevac IM300 by SK Functional polyomer

[0171] Intermediate layer 2: 200 μm thick film of functionalized polypropylene sold under the trade name Orevac CA100 by SK Functional polyomer

[0172] Representative structures of the invention are prepared by heat-bonding: Composition A or B / intermediate layer / copper This assembly, surrounded by a frame of identical thickness to the total assembly, is compressed in a press at 220°C. The press plates are brought into contact with the superimposed layers for 90s without applying pressure. Then, a pressure of 50 bar is applied for 60s. Finally, the assembly is cooled for 2 min while maintaining a pressure of 30 bar. The comparative examples are prepared in the same way without an intermediate layer. [Tables 5] Inv 1 Inv 2 Inv 3 Inv 4 Comp 1 Comp 2 Layer of Compo- Compo- Compo- Compo- Compo- Compo- coating sition A sition A sition B sition B sition A sition B Intermediate layer Orevac ®IM300 Orevac ®CA100 Orevac ®IM300 Orevac ®CA100 without without Table 5 Evaluation of color variation

[0173] The copper structures covered with the compositions are aged at 150°C for 240 hours in a ventilated study.

[0174] The colorimetric properties of aged product surfaces are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and component specular included.

[0175] The evolution of the color of the samples during aging expressed by the parameter AE. This is calculated according to the following equation:

[0176] :A2......;...... / 5...... / 7*......, >,2 AE= - L o ) +(a f - has Q ) +\ b - b0)

[0177] In this equation, L*, a* and b* represent the values ​​measured on the aged plate, at t = 240h and Lo*, ao* and b0* represent the values ​​measured on the unaged plates. The higher the value of AE, the more the color has evolved during aging, illustrating the instability of the composition.

[0178] The results of the evaluation tests are given in Table 6 [Tableauxô] Inv 1 Inv 2 Inv 3 Inv 4 Comp 1 Comp 2 Color variation AE after aging 150°C 240h 8 9 7 9 15 13 Evaluation of adhesion at the metal / polymer interface:

[0179] Adhesion at the copper / polyolefin interface is measured by a peel test using a dynamometer according to standard NF EN 28510-1:2014. A 7 mm wide polymer strip is cut using a die cutter within the exemplified structures. One end of this strip is fixed to the moving part of the dynamometer while the rest of the sample is held horizontally. Peeling is achieved by vertical movement of the moving part of the dynamometer at a speed of 50 mm / min. The force sensor records the adhesion force opposing this peeling.

[0180] The results of the evaluation tests are given in Table 7 [Tables 7] Inv 1 Inv 2 Inv 3 Inv 4 Comp 1 Comp 2 Peeling force (N / cm) 24 16 25 19 <5 <5

[0181] The examples show that the structures according to the invention have good mechanical properties and exhibit color stability over time and good adhesion of the coating layer.

Claims

1.

2.

3.

4. Claims An electricity transport component, wherein the electricity transport component comprises a metal surface, characterized in that said metal surface is coated over its entire surface with: - an intermediate layer of polyolefin; and - a coating layer of an electrically insulating composition comprising predominantly at least one polyamide whose number of carbon atoms per nitrogen atom is greater than 6.5 and at least one coloring matter, the intermediate layer being positioned between the metal surface of the electricity transport component and the coating layer. An electricity transport component according to claim 1, being an interconnection bar. An electricity transmission component according to claim 1 or 2, wherein the metal surface is copper, copper alloy, aluminum or aluminum alloy. Electricity transmission component according to any one of the preceding claims, in which the polyolefin is chosen from: - non-functionalized polyolefins (B2) in particular homopolymer or copolymer of alpha olefins or diolefins, such as for example, ethylene, propylene, butene-1, octene-1, butadiene, preferably homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene; homopolymers or copolymers of propylene; ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM);styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers, copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (for example methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer being able to reach 40% by weight; - functionalized polyolefins (Bl) chosen from a polymer alpha olefins having reactive units of the acid, anhydride or epoxy function type, for example polyolefins (B2) grafted or co- or terpolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid or by carboxylic acid anhydrides such as maleic anhydride; - mixtures thereof.

5. An electricity transport component according to any one of the preceding claims, wherein the intermediate layer of polyolefin has a thickness of between 10 and 1000 pm, preferably between 30 and 500 pm, advantageously between 50 and 300 pm.

6. An electricity transport component according to any one of the preceding claims, characterized in that the coloring matter content ranges from 0.5 to 10% by weight, preferably from 1 to 5% by weight relative to the total weight of the composition.

7. Electricity transport component according to any one of the preceding claims, characterized in that the polyamide(s) have an inherent viscosity measured according to standard ISO 307:2007 greater than 1.

1.

8. Electricity transport component according to any one of the preceding claims, characterized in that the polyamide(s) have an enthalpy of fusion measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly greater than 20 J / g.

9. Electricity transport component according to any one of the preceding claims, characterized in that the polyamide(s) have a crystallization temperature measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly less than 180°C.

10. Electricity transport component according to any one of the preceding claims, characterized in that the polyamide is chosen from a PAU, PA12, PA1010, PA 1012, PA 610, PA 612, PA 613, PA 912, PA 516, PA 6 / 11, PA 6 / 12, PA 11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture, more particularly PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA 12, preferably the PAU.

11. An electricity transmission component according to any one of the re- preceding claims characterized in that the polyamide(s) of the composition of the coating layer have a difference, expressed in absolute value, between its total acidity and its total basicity of less than 70 and a basicity of the total polyamide(s) of less than 60 peq / g.

12. Electricity transport component according to any one of the preceding claims, characterized in that the polyamide(s) of the composition of the coating layer have a total acidity of less than 60 peq / g.

13. A method of preparing an electricity transport component according to any one of claims 1 to 12 comprising: - a step of coating the entire metal surface of the electricity transport component with an intermediate polyolefin layer as defined in any one of claims 1, 4 and 5; then - a step of coating the intermediate polyolefin layer with a coating composition as defined in any one of claims 1 and 6 to 12.

14. A method according to claim 13, characterized in that the step of coating the intermediate layer is carried out by extrusion.

15. A method according to claim 13, characterized in that the step of coating the intermediate layer is carried out by depositing a powder of said coating composition and then melting the powder.