Electrical connection device with increased fire resistance

Abstract

The invention relates to an electrical connection device (1) comprising a longitudinally extending conductive element (2) covered with a thermally insulating sheath (3) made of a polyaryl ether ketone material. Figure for the abstract: Fig. 1

Description

Title of the invention: Electrical connection device with increased fire resistance technical field

[0001] The present invention relates to the technical field of electrical connection devices, and finds an advantageous application in the field of battery packs for electric motor vehicles, without this being limiting. Previous art

[0002] It is known from the prior art of electrical connection devices comprising a conductive element extending longitudinally, for example in the form of a braid, a cable, a multilayer or single-layer strip, and covered with a thermally insulating sheath.

[0003] In this field of application, the conductive element is inherently flexible or rigid so that it can be shaped to follow a specific path in order to make the electrical connection between two devices. The conductive element is, for example, made of copper or aluminum, plated, tinned or nickel-plated, or of other conductive materials, sometimes in alternating layers.

[0004] The conductive element is thermally insulated by the peripheral extrusion of a sheath made of suitable material, such as so-called "high performance" PVC, in that it resists, for example, a temperature of around 125°C.

[0005] In the field of automotive electrical conductivity, particularly in the context of electric vehicle battery packs or power busbars used in these vehicles, it is known that the sheathing is made of PA 11, PA 12, or PVC polyamide, which meets the UL94V-0 standard for the flammability of plastic materials. Specifically, the V-0 rating requires that vertical combustion cease after 10 seconds; while some flow is permitted, it must not be burned.

[0006] However, in the field of electric vehicles, the new regulations in force, namely ECE Regulation R. 100 Rev.2 / UNR100 (Uniform provisions for the type approval of battery electric vehicles with regard to specific requirements for construction, functional safety and hydrogen emissions), which defines the safety procedures in the event of a fire in an electric vehicle, require that in the event of a vehicle fire, the batteries must continue to operate for 5 minutes to allow the evacuation of passengers.

[0007] In particular, the test conforming to standard R100 is intended to verify the battery's operational safety (SRSEE) in the event of exposure to a fire originating outside the vehicle, for example, following a fuel leak from a vehicle (either the vehicle itself or a nearby vehicle). The driver and passengers must then have enough time (5 minutes) to evacuate the vehicle.

[0008] To meet said R100 standard, some companies attempt to thermally insulate the entire battery pack with components having low flammability, such as polyamide PA 12 meeting the UL94V 0 standard.

[0009] This complex solution is not entirely satisfactory because the electrical connection devices and the power bus bars which run out of the battery pack through the vehicle are therefore not covered by said reinforced insulation.

[0010] The Applicant also noted that the sheaths of the electrical connection devices made of PAU, PA 12 or PVC do not meet the R 100 standard.

[0011] Without knowing whether they meet the R100 standard, there are other Thermally insulated electrical connection devices, sheathed in a mineral material such as mica, are possible, but their implementation is complex and expensive. Description of the invention

[0012] One of the aims of the invention is to overcome the disadvantages of the prior art by proposing an electrical connection device, preferably used to connect battery packs or as power bars and electrical interconnection, which makes it possible to satisfy the R 100 standard, by resisting to about 500° for at least 5 min, under an electrical voltage greater than 500 V without dielectric breakdown.

[0013] For this purpose, and according to the invention, an electrical connection device has been developed comprising a longitudinally extending conductive element, and covered with a thermally insulating sheath made of a material comprising polyarylene ether-ketone (PAEK), also referred to as polyaryl ether-ketone.

[0014] As is known per se, PAEKs consist of aromatic (aryl) rings linked by an oxygen atom (ether) and / or a carbonyl group (ketone). Their properties depend primarily on the ether / ketone ratio. In the abbreviations used in this text, A denotes an aryl group, E denotes an ether group, and K denotes a ketone group. Hereafter, these abbreviations will be used instead of the common names for the compounds to which they refer.

[0015] The Applicant has carried out tests and found that the connection device according to the invention meets the R100 standard in that it withstands 500°C for 5 min.

[0016] Preferably, PAEK is present in the material in a mass fraction of at least 50% relative to the total weight of the material, more preferably at least 80%, and even more preferably at least 95% to 100%. The material may be composed of (100%) or essentially composed of PAEK, it being understood that the The 100% content should be qualified by the possible presence of additives of all kinds, both chemical and mechanical, for example carbon fibers, or impurities.

[0017] In different embodiments, the PAEK is chosen from:

[0018] - A polyetherketone (PEK), comprising motifs of the type of formula I next:

[0019] [Chem.l]

[0020] - A polyetheretherketone (PEEK), comprising motifs of the type of formula II next:

[0021] [Chem.2]

[0022] - A polyetherketoneketone (PEKK), comprising motifs of the formula type Next III:

[0023] [Chem.3]

[0024] - A poly-ether-ether-ketone-ketone (PEEKK), comprising motifs of the type of Formula IV follows:

[0025] [Chem.4]

[0026] Of course, other arrangements of the carbonyl group and the oxygen atom are possible, however, without departing from the scope of the invention.

[0027] According to a preferred embodiment, the PAEK of the material constituting the sheath comprises PEKK, or PEKK copolymers. PEKK offers the advantage of exhibiting even higher temperature resistance than other PAEKs, in particular PEEK or PEK, which makes it all the more useful for the production of the sheath implemented in the invention, which must withstand the high heat released during a fire.

[0028] According to other advantageous features, taken alone or in combination: - the conductive element is in the form of a strip, or a flat / profile rigid ; - the strip is multilayered, for example of the type with an aluminium core between two layers of copper; - the metal strip is made of copper; - the sheath is extruded around the conductive element. Brief description of the drawings

[0029] The features and advantages of the invention will become clearer from the following description, given by way of non-limiting example, with reference to the single attached figure, in which:

[0030] [Fig-1] is a schematic view illustrating in perspective a connection device according to the invention with a single-layer strip.

[0031] [Fig.2] is a schematic view illustrating in perspective a connection device according to the invention with a multilayer strip. Detailed description of the invention

[0032] With reference to Figures 1 and 2, the invention relates to an electrical connection device (1) well known to those skilled in the art in that it comprises an electrically conductive element (2) extending longitudinally, covered with a thermally insulating sheath (3) extruded around the conductive element (2).

[0033] This type of connection device (1) is mainly used in the field of power transmission, for replacing cables, rigid busbars, in electrical equipment (cabinets, circuit breakers, inverters), low voltage electrical switchboards, transformers (connection between the busbar and the transformer), in automotive electrical connections, for example in vehicle battery packs.

[0034] The conductive element (2) of the device (1) may be in the form of a metal braid, a cable, or any other suitable conductive element. According to the embodiment illustrated in [Fig. 1], the conductive element (2) comprises, for example, a single strip of copper or aluminum, bare or plated, tin-plated or nickel-plated, or having an aluminum core coated on both sides with copper, or a copper core coated on both sides with aluminum, or, as illustrated in [Fig. 2], the conductive element (2) comprises a stack of strips (4), for example of copper or aluminum, or alternating copper / aluminum, having, for example, a width from 9 to 120 mm, with each strip (4) having a thickness, for example, from 0.5 mm to 1 mm.

[0035] The invention lies in the fact that the sheath (3) is made of a material comprising polyarylene-ether-ketone (PAEK), also referred to as polyaryl-ether-ketone.

[0036] Preferably, the material can be made of (100%), or essentially made of of PAEK, it being understood that the 100% content is subject to the possible presence of additives of all kinds, for example carbon fibers, or impurities.

[0037] The PAEK of the material constituting the sheath (3) comprises PEKK, or PEKK copolymers. PEKK offers the advantage of exhibiting even higher temperature resistance than other PAEKs, in particular PEEK or PEK, which makes it all the more useful for the manufacture of the sheath (3) implemented in the invention, which must withstand the high heat released during a fire.

[0038] The tested device (1) is subjected to direct and indirect exposure to a flame produced by the combustion of a commercial fuel, according to the requirements of Annex 8E of UNECE Regulation No. 100 (Rev2) (ECE R100 Rev2).

[0039] According to this test, the device (1) is subjected to a direct pool fire for 70 seconds. Subsequently, the device (1) is exposed to an indirect fire for 60 seconds (interposition of a refractory brick screen).

[0040] The result of this test demonstrated that the device (1) could withstand 500°C for 5 minutes, under an electrical voltage exceeding 500 V without dielectric breakdown, thus meeting the R100 standard. By "withstand," it is understood that the sheath (3) retains its integrity and provides thermal insulation for the conductive element (2), while the conductive element continues to perform its electrical conduction function.

Claims

Demands

1. Electrical connection device (1) intended for use in connecting battery packs or as power and electrical interconnection bars, comprising a conductive element (2) in the form of a longitudinally extending strip (4) covered with a thermally insulating sheath (3) characterized in that the insulating sheath (3) is extruded around the strip (4) and is made of a material comprising polyaryl-ether-ketone.

2. Device (1) according to claim 1, characterized in that the polyaryl-ether-ketone is present in the material in a mass fraction of at least 50% relative to the total weight of material, more preferably of at least 80%, and even more preferably of at least 95% to 100%.

3. Device (1) according to any one of the preceding claims, characterized in that the material comprises poly-ether-ketone-ketone

4. Device (1) according to claim 1, characterized in that the strip (4) is multilayered.

5. Device (1) according to any one of claims 1 to 4, characterized in that the strip (4) is made of copper or aluminum.

Images