Busbar for battery assembly

Abstract

A bus bar is provided that includes an insulating portion covering at least a portion of an electrical conductor. The insulating portion includes a polymer composition including a polymer matrix including a thermotropic liquid crystal polymer. Further, the polymer composition exhibits a melt viscosity of about 300 Pa-s or less as determined according to ISO 11443: 2021 at a shear rate of 1,000 s-1 and a temperature of about 15 DEG C higher than the melting temperature of the composition, and a load deflection temperature of about 170 DEG C or more as determined according to ISO 75: 2013 under a load of 1.8 MPa.

Description

[0001] Related Applications

[0002] This application is based upon and claims priority to U.S. Provisional Patent Application Serial No. 63 / 391,338, filed on July 22, 2022, which is incorporated herein by reference. Background Art

[0003] An electric vehicle, such as a battery electric vehicle, a plug-in hybrid electric vehicle, a mild hybrid electric vehicle, or a full hybrid electric vehicle, typically has an electric powertrain that includes an electric propulsion source (e.g., a battery) and a transmission. Plastic insulating materials are typically used in electric vehicles to insulate busbars that are used to connect individual battery cells within the battery. However, one problem with many conventional materials is that they lack the heat resistance required for high voltage applications. In addition, attempts to use high performance polymers have led to other problems, such as low mechanical strength. Therefore, there is a need for a busbar, such as for an electric vehicle, that includes an insulating portion having a good combination of insulating properties, heat resistance, and mechanical strength. Summary of the invention

[0004] According to one embodiment of the present invention, a busbar is disclosed, which includes an insulating portion covering at least a portion of an electrical conductor. The insulating portion includes a polymer composition, the polymer composition including a polymer matrix including a thermotropic liquid crystal polymer. Further, the polymer composition exhibits a thermal conductivity of 1000 s at 1,000 s according to ISO 11443:2021. -1 The invention also provides a melt viscosity of about 300 Pa-s or less measured at a shear rate of about 1000 Pa and a temperature about 15°C higher than the melting temperature of the composition, and a deflection temperature under load of about 170°C or more measured under a load of 1.8 MPa according to ISO 75:2013.

[0005] Other features and aspects of the present invention are described in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A full and enabling disclosure of the present invention including the best mode thereof that occurs to one of ordinary skill in the art is more particularly set forth in the remainder of the specification including reference to the accompanying drawings, which include:

[0007] Figure 1 One embodiment of a busbar that may be formed according to the present invention is shown;

[0008] Figure 2 Another embodiment of a busbar that may be formed according to the present invention is shown;

[0009] Figure 3 shows a cross-sectional view of a portion of a busbar that may be formed in accordance with the present invention, including an insulating coating;

[0010] Figure 4 shows the end of one embodiment of a busbar that may be formed in accordance with the present invention;

[0011] Figure 5 An embodiment of an electric vehicle that can employ the high-voltage electrical component of the present invention is shown;

[0012] Figure 6 A battery assembly in which the high voltage electrical components of the present invention may be employed is shown;

[0013] Figure 7 Two perspective views of a bus bar that may be used in the present invention and is aligned with a plurality of battery cells are shown;

[0014] Figure 8 A battery assembly including a housing that can be used in the present invention is shown. Figure 7 The busbar in

[0015] Fig. 9 Another embodiment of a bus bar that can be used in the present invention to align with multiple battery cells is shown; and

[0016] Fig.10 Another embodiment of a battery assembly that can be used in the present invention is shown.

[0017] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention. DETAILED DESCRIPTION

[0018] Those skilled in the art will appreciate that the current discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0019] Generally speaking, the present invention relates to a busbar that can be used for a battery assembly of an electric vehicle, such as a battery-powered electric vehicle, a fuel cell-powered electric vehicle, a plug-in hybrid electric vehicle (PHEV), a mild hybrid electric vehicle (MHEV), a full hybrid electric vehicle (FHEV), etc. The busbar generally includes an insulating portion that covers at least a portion of an electrical conductor (e.g., a metal). Notably, the insulating portion comprises a polymer composition that comprises a liquid crystal polymer and exhibits a combination of high fluidity and good heat resistance. More specifically, the composition may exhibit a melt viscosity of about 300 Pa-s or less, in some embodiments about 150 Pa-s or less, in some embodiments about 5 to about 100 Pa-s, in some embodiments about 10 to about 95 Pa-s, and in some embodiments about 15 to about 80 Pa-s, which is according to ISO 11443:2021 at 1,000 s. -1The shear rate and the temperature (e.g., about 350°C) higher than the melting temperature of the composition are measured. The deflection temperature under load (DTUL) is a measure of short-term heat resistance, which may also remain relatively high. For example, the DTUL may be about 170°C or higher, about 200°C or higher in some embodiments, about 210°C to about 300°C in some embodiments, and about 220°C to about 280°C in some embodiments, for example, according to ISO 75:2013 under a load of 1.8MPa. Even at such a DTUL value, the ratio of the melting temperature to the DTUL value may remain relatively high. For example, the ratio may be in the range of about 0.5 to about 1.00, about 0.6 to about 0.95 in some embodiments, and about 0.65 to about 0.85 in some embodiments. The specific melting temperature of the polymer composition may be, for example, about 250°C to about 440°C, about 260°C to about 400°C in some embodiments, and about 300°C to about 380°C in some embodiments.

[0020] In addition to showing good flow properties and heat resistance, the polymer composition can also show high thermal conductivity. This high thermal conductivity value allows the composition to form a thermal path so that heat is transferred from the conductive element of the busbar. In this way, "hot spots" can be quickly eliminated, and the overall temperature can be reduced during use. For example, the polymer composition can show about 2W / mK or higher, about 2.5 to about 15W / mK in some embodiments, about 3 to about 10W / mK in some embodiments, and about 4 to about 8W / mK in-plane (or "flow") thermal conductivity in some embodiments, which is determined according to ASTM E 1461-13 (2022). Similarly, the polymer composition can show about 0.8W / mK or higher, about 1 to about 12W / mK in some embodiments, and about 2 to about 8W / mK in some embodiments. The cross-plane (or "cross flow") thermal conductivity is determined according to ASTM E 1461-13 (2022). The composition may also exhibit a through-plane thermal conductivity of about 0.2 W / mK or more, in some embodiments, about 0.3 W / mK or more, in some embodiments, from about 0.5 to about 4 W / mK, and in some embodiments, from about 0.6 to about 2 W / mK, as measured in accordance with ASTM E 1461-13 (2022).

[0021] Despite the thermal conductivity, the polymer composition can still have electrical insulation and can maintain a high short-term dielectric strength even when exposed to an electric field. "Dielectric strength" generally refers to the voltage that a material can withstand before breakdown occurs. For example, the polymer composition can generally exhibit a dielectric strength of about 10 kilovolts / millimeter (kV / mm) or more, about 15 kV / mm or more in some embodiments, and about 25 kV / mm to about 60 kV / mm in some embodiments, for example, according to IEC 60234-1:2013. The insulating properties of the polymer composition can also be characterized by a high relative tracking index (CTI), for example, about 150 volts or more, about 170 volts or more in some embodiments, about 200 volts or more in some embodiments, and about 220 to about 350 volts in some embodiments, for example, according to IEC 60112:2003 at 3 mm thickness.

[0022] Despite the above characteristics, the polymer composition can still maintain high strength, thereby providing enhanced flexibility and impact resistance. For example, the polymer composition can exhibit a tensile stress at break (i.e., strength) of about 40 MPa to about 300 MPa, about 50 MPa to about 250 MPa in some embodiments, and about 70 to about 200 MPa in some embodiments; about 0.5% or more, about 1% to about 8% in some embodiments, and about 2% to about 5% tensile strain at break (i.e., elongation) in some embodiments; and / or about 5,000 to about 30,000 MPa, about 6,000 MPa to about 25,000 MPa in some embodiments, and about 9,000 MPa to about 22,000 MPa in some embodiments. Tensile properties can be determined according to ISO 527:2019 at a temperature of 23 ° C. The composition may also exhibit a flexural strength of about 20 MPa or greater, in some embodiments about 50 to about 300 MPa, in some embodiments about 70 to about 250 MPa, in some embodiments about 80 to about 200 MPa; and / or a flexural modulus of about 10,000 MPa or less, in some embodiments about 5,000 MPa to about 30,000 MPa, in some embodiments about 8,000 MPa to about 25,000 MPa, and in some embodiments about 9,000 MPa to about 20,000 MPa. Flexural properties may be measured at a temperature of 23° C. according to ISO 178:2019. The polymer composition may also exhibit high impact strength, which may provide enhanced flexibility to the resulting part. For example, the polymer composition may exhibit a flexural modulus of about 2 kJ / m 2 or greater, in some embodiments from about 4 to about 20 kJ / m 2 , and in some embodiments from about 6 to about 18 kJ / m 2Unnotched Charpy impact strength of about 10 kJ / m 2 or greater, in some embodiments from about 15 to about 50 kJ / m 2 , and in some embodiments from about 20 to about 40 kJ / m 2 The notched charpy impact strength is measured according to ISO 179-1:2010 at a temperature of 23°C.

[0023] The polymer compositions can achieve the unique combination of properties described above even at relatively small thickness values, such as about 8 mm or less, in some embodiments about 4 mm or less, in some embodiments about 0.2 to about 3.2 mm or less, in some embodiments about 0.4 to about 1.6 mm, and in some embodiments about 0.4 to about 0.8 mm.

[0024] Various aspects of the invention will now be described in further detail.

[0025] I. Polymer composition

[0026] A. Polymer Matrix

[0027] As described above, the polymer matrix includes at least one liquid crystal polymer. For example, the liquid crystal polymer generally accounts for about 50 wt.% to 100 wt.%, in some embodiments, about 70 wt.% to 100 wt.%, and in some embodiments, about 90 wt.% to 100 wt.% (e.g., 100 wt.%) of the polymer matrix. Liquid crystal polymers are generally classified as "thermotropic" in that they can have a rod-like structure and exhibit crystallization behavior in their molten state (e.g., thermotropic nematic state). Such polymers generally have a DTUL value of about 200°C to about 340°C, in some embodiments, about 210°C to about 300°C, and in some embodiments, about 220°C to about 280°C, which is measured under a load of 1.8 MPa according to ISO 75-2:2013. The polymer also has a relatively high melting temperature, which is, for example, about 250°C to about 440°C, in some embodiments, about 260°C to about 400°C, and in some embodiments, about 300°C to about 380°C. The polymer may be formed from one or more types of repeating units known in the art. For example, a liquid crystal polymer may contain one or more aromatic ester repeating units generally represented by the following formula (I):

[0028]

[0029] in

[0030] Ring B is a substituted or unsubstituted 6-membered aryl group (e.g., 1,4-phenylene or 1,3-phenylene), a substituted or unsubstituted 6-membered aryl group fused to a substituted or unsubstituted 5-membered or 6-membered aryl group (e.g., 2,6-naphthalene), or a substituted or unsubstituted 6-membered aryl group linked to a substituted or unsubstituted 5-membered or 6-membered aryl group (e.g., 4,4-biphenylene); and

[0031] Y1 and Y2 are independently O, C(O), NH, C(O)HN or NHC(O).

[0032] Typically, at least one of Y1 and Y2 is C(O). Examples of such aromatic ester repeating units may include, for example, aromatic dicarboxyl repeating units (Y1 and Y2 in Formula I are C(O)), aromatic hydroxycarboxyl repeating units (Y1 in Formula I is O, and Y2 is C(O)), and various combinations thereof.

[0033] For example, aromatic hydroxycarboxylic repeating units derived from aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid; 4-hydroxy-4'-biphenylcarboxylic acid; 2-hydroxy-6-naphthoic acid; 2-hydroxy-5-naphthoic acid; 3-hydroxy-2-naphthoic acid; 2-hydroxy-3-naphthoic acid; 4'-hydroxyphenyl-4-benzoic acid; 3'-hydroxyphenyl-4-benzoic acid; 4'-hydroxyphenyl-3-benzoic acid, etc., as well as alkyl, alkoxy, aryl and halogen substitutes and combinations thereof can be used. Particularly suitable aromatic hydroxycarboxylic acids are 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA). When used, repeating units derived from hydroxycarboxylic acids (e.g., HBA and / or HNA) typically account for about 20 mol.% to about 80 mol.%, in some embodiments about 25 mol.% to about 75 mol.%, and in some embodiments about 30 mol.% to 70 mol.%.

[0034] Aromatic dicarboxylic repeating units derived from aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4'-dicarboxybiphenyl, bis(4-carboxyphenyl)ether, bis(4-carboxyphenyl)butane, bis(4-carboxyphenyl)ethane, bis(3-carboxyphenyl)ether, bis(3-carboxyphenyl)ethane, and the like, as well as alkyl, alkoxy, aryl and halogen substitutes thereof and combinations thereof, can also be used. Particularly suitable aromatic dicarboxylic acids can include, for example, terephthalic acid (TA), isophthalic acid (IA) and 2,6-naphthalene dicarboxylic acid (NDA). When used, repeating units derived from aromatic dicarboxylic acids (e.g., IA, TA, and / or NDA) typically comprise from about 1 mol.% to about 50 mol.%, in some embodiments, from about 5 mol.% to about 40 mol.%, and in some embodiments, from about 10 mol.% to about 35% of the polymer.

[0035] Other repeating units can also be used in the polymer.For example, in certain embodiments, it is possible to use repeating units derived from aromatic diols, such as hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dimethylbiphenyl (or 4,4'-biphenol), 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, bis(4-hydroxyphenyl)ethane, etc. and alkyl, alkoxy, aryl and halogen substituents and combinations thereof. Particularly suitable aromatic diols can include, for example, hydroquinone (HQ) and 4,4'-biphenol (BP). When used, repeating units derived from aromatic diols (for example, HQ and / or BP) generally account for about 1% to about 40mol.%, about 2mol.% to about 35mol.% in some embodiments, and about 5mol.% to about 30% in some embodiments of the polymer. Repeating units, such as those derived from aromatic amides (e.g., acetaminophen (APAP)) and / or aromatic amines (e.g., 4-aminophenol (AP), 3-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, etc.) may also be used. When used, repeating units derived from aromatic amides (e.g., APAP) and / or aromatic amines (e.g., AP) typically comprise from about 0.1 mol.% to about 20 mol.%, in some embodiments from about 0.5 mol.% to about 15 mol.%, and in some embodiments from about 1 mol.% to about 10 mol.% of the polymer. It should also be understood that various other monomer repeating units may be incorporated into the polymer. For example, in certain embodiments, the polymer may contain one or more repeating units derived from non-aromatic monomers (e.g., aliphatic or alicyclic hydroxycarboxylic acids, dicarboxylic acids, diols, amides, amines, etc.). Of course, in other embodiments, the polymer can be "wholly aromatic," meaning that it lacks repeating units derived from non-aromatic (eg, aliphatic or cycloaliphatic) monomers.

[0036] Although not required, in the aspect that the liquid crystal polymer contains relatively high content of repeating units derived from naphthalene hydroxycarboxylic acid and naphthalene dicarboxylic acid (e.g., NDA, HNA or a combination thereof), the liquid crystal polymer can be a "high naphthalene" polymer. That is, the total amount of repeating units derived from naphthalene hydroxycarboxylic acid and / or naphthalene dicarboxylic acid (e.g., NDA, HNA or a combination of HNA and NDA) is generally about 10 mol.% or more of the polymer, in some embodiments about 12 mol.% or more, in some embodiments about 15 mol.% or more, in some embodiments about 15 mol.% to about 50 mol.%, and in some embodiments about 16 mol.% to about 30 mol.%. For example, in one embodiment, the repeating units derived from NDA are within the above range. The liquid crystal polymer may also include various other monomers. For example, the polymer may contain about 20 mol.% to about 60 mol.% of repeating units derived from HBA, in some embodiments, about 25 mol.% to about 55 mol.% of repeating units derived from HBA, and in some embodiments, about 30 mol.% to about 50 mol.% of repeating units derived from HBA. The polymer may also contain about 1 mol.% to about 15 mol.% of aromatic dicarboxylic acids (e.g., IA and / or TA) and / or about 10 mol.% to about 35 mol.% of aromatic diols (e.g., BP and / or HQ). Of course, in other embodiments, the liquid crystal polymer may be a "low naphthalene" polymer containing a relatively low content of repeating units derived from naphthalene hydroxycarboxylic acids and naphthalene dicarboxylic acids (e.g., naphthalene-2,6-dicarboxylic acid (NDA), 6-hydroxy-2-naphthoic acid (HNA) or a combination thereof). That is, the total amount of repeating units derived from naphthalenehydroxycarboxylic acid and / or naphthalene dicarboxylic acid (e.g., NDA, HNA, or a combination of HNA and NDA) can be about 10 mol.% or less, in some embodiments about 8 mol.% or less, and in some embodiments, from about 1 mol.% to about 6 mol.% of the polymer.

[0037] It is generally desirable that a considerable portion of the polymer matrix is ​​formed by such high naphthalene polymers. For example, the high naphthalene polymers described herein generally account for 50 wt.% or more of the polymer matrix, in some embodiments about 65 wt.% or more, in some embodiments about 70 wt.% to 100 wt.%, in some embodiments about 80 wt.% to 100% (e.g., 100 wt.%). In some cases, blends of polymers may also be used. For example, low naphthalene liquid crystal polymers may account for about 1 wt.% to about 50 wt.% of the total amount of liquid crystal polymer in the composition, in some embodiments about 2 wt.% to about 40 wt.%, and in some embodiments about 5 wt.% to about 30 wt.%, while high naphthalene liquid crystal polymers may account for about 50 wt.% to about 99 wt.% of the total amount of liquid crystal polymer in the composition, in some embodiments about 60 wt.% to about 98 wt.%, and in some embodiments about 70 wt.% to about 95 wt.%.

[0038] B. Optional additives

[0039] In certain embodiments, the polymer composition may be formed entirely of a polymer matrix (i.e., 100 wt.%). Of course, in other embodiments, one or more additives may be distributed throughout the polymer matrix to help provide the desired properties. When used, such additives are typically from about 0.1 to about 300 parts by weight per 100 parts by weight of the polymer matrix, from about 0.5 to about 250 parts by weight in some embodiments, and from about 1 to about 200 parts by weight in some embodiments. The additive may, for example, account for from about 0.1 wt.% to about 80 wt.% of the polymer composition, from about 0.5 wt.% to about 70 wt.% in some embodiments, and from about 1 wt.% to about 60 wt.% in some embodiments.

[0040] For example, in a particular embodiment, the polymer composition may include a thermally conductive filler distributed within the polymer matrix. In order to help achieve the desired balance between thermal conductivity, high flowability and good mechanical properties, the relative amount of the thermally conductive filler is generally controlled to be about 10 to about 250 parts by weight per 100 parts by weight of the polymer matrix, about 40 to about 250 parts by weight in some embodiments, about 60 to about 200 parts by weight in some embodiments, and about 80 to about 190 parts by weight in some embodiments. The thermally conductive filler may, for example, account for about 20 wt.% to about 70 wt.% of the polymer composition, about 28 wt.% to about 62 wt.% in some embodiments, about 35 wt.% to about 65 wt.% in some embodiments, and about 40 wt.% to about 60 wt.% in some embodiments.

[0041] If desired, thermally conductive fillers may include materials with high intrinsic thermal conductivity. For example, polymer compositions may include materials with 50W / mK or higher, 100W / mK or higher, and 150W / mK or higher intrinsic thermal conductivity in some embodiments. Examples of such high intrinsic thermal conductive materials may include, for example, boron nitride, aluminum nitride, magnesium silicon nitride, graphite (e.g., expanded graphite), silicon carbide, carbon nanotubes, zinc oxide, magnesium oxide, beryllium oxide, zirconium oxide, yttrium oxide, aluminum powder, and copper powder. Although such materials may be used in certain embodiments, it has been found that high thermal conductivity can be achieved without the use of conventional materials with high intrinsic thermal conductivity. For example, polymer compositions may generally be free of fillers with intrinsic thermal conductivity. That is, such fillers may account for about 10wt.% or less of the polymer composition, about 5wt.% or less in some embodiments, and 0wt.% to about 2wt.% (e.g., 0wt.%) in some embodiments.

[0042] For example, in a particular embodiment, thermally conductive filler can include mineral particles. When used, such mineral particles are generally about 70 to about 250 weight parts per 100 weight parts of polymer matrix, about 75 to about 200 weight parts in some embodiments, and about 90 to about 190 weight parts in some embodiments. Mineral particles can for example account for about 30wt.% to about 70wt.% of polymer composition, about 35wt.% to about 65wt.% in some embodiments, and about 40wt.% to about 60wt.% in some embodiments. Mineral particles can be formed by natural and / or synthetic silicate minerals, such as talc, mica, halloysite, kaolinite, illite, montmorillonite, vermiculite, palygorskite, pyrophyllite, calcium silicate, aluminum silicate, wollastonite, etc. Talc is particularly suitable for polymer composition. The shape of the particle can be changed as required, such as granular, flaky, etc. The median particle size (D50) of the particles is generally from about 1 to about 25 microns, in some embodiments from about 2 to about 15 microns, and in some embodiments from about 4 to about 10 microns, as measured by sedimentation analysis (e.g., Sedigraph 5120). If desired, the particles may also have a high specific surface area, such as about 1 square meter per gram (m2 / g). 2 / g) to about 50m 2 / g, in some embodiments about 1.5m 2 / g to about 25m 2 / g, and in some embodiments about 2m 2 / g to about 15m 2 / g. The surface area can be determined by the physical gas adsorption (BET) method (nitrogen as adsorbed gas) according to DIN 66131:1993. The water content can also be relatively low, for example, about 5% or less, in some embodiments about 3% or less, and in some embodiments about 0.1 to about 1%, as determined according to ISO 787-2:1981 at a temperature of 105°C.

[0043] In addition to and / or in place of the mineral particles, the thermally conductive filler may also include mineral fibers (also referred to as "whiskers"). When used, such mineral fibers are typically present in an amount of about 10 to about 150 parts by weight, in some embodiments about 15 to about 100 parts by weight, and in some embodiments about 20 to about 80 parts by weight per 100 parts by weight of the polymer matrix. The mineral fibers may, for example, comprise about 10 wt.% to about 50 wt.%, in some embodiments about 15 wt.% to about 45 wt.%, and in some embodiments about 20 wt.% to about 40 wt.% of the polymer composition. Examples of such mineral fibers include those derived from silicates, such as monoisland silicates, archipelagic silicates, inosilicates (e.g., calcium inosilicates such as wollastonite; calcium magnesium inosilicates such as tremolite; calcium magnesium iron inosilicates such as actinolite; magnesium iron inosilicates such as anthophyllite; etc.), layered silicates (e.g., aluminum layered silicates such as palygorskite), reticular silicates, etc.; sulfates, such as calcium sulfate (e.g., dehydrated or anhydrite); mineral wool (e.g., rock wool or slag wool); etc. Particularly suitable are inosilicates, such as those available from Nyco Minerals under the trade name (For example 4W or 8) obtained wollastonite fibers. The median diameter of the mineral fiber may be from about 1 to about 35 microns, from about 2 to about 20 microns in some embodiments, from about 3 to about 15 microns in some embodiments, and from about 7 to about 12 microns in some embodiments. The mineral fiber may also have a narrow size distribution. That is, at least about 60 vol.% of the fiber, at least about 70 vol.% of the fiber in some embodiments, and at least about 80 vol.% of the fiber in some embodiments may have a size within the above range. In addition to having the above-mentioned size characteristics, the mineral fiber may also have a relatively high aspect ratio (average length divided by the median diameter) to help further improve the mechanical properties and surface quality of the resulting polymer composition. For example, the aspect ratio of the mineral fiber may be from about 2 to about 100, from about 2 to about 50 in some embodiments, from about 3 to about 20 in some embodiments, and from about 4 to about 15 in some embodiments. The volume average length of such mineral fibers may be, for example, from about 1 to about 200 microns, from about 2 to about 150 microns in some embodiments, from about 5 to about 100 microns in some embodiments, and from about 10 to about 50 microns in some embodiments.

[0044] The polymer composition can also include various other optional components to help improve its overall performance. For example, the polymer composition can include a metal hydroxide that can effectively "lose" hydroxide ions during processing with the polymer to initiate chain scission of the polymer, thereby reducing the molecular weight, thereby reducing the melt viscosity of the polymer under shear. When used, the metal hydroxide can be about 0.05 to about 10 parts by weight per 100 parts by weight of the polymer matrix, about 0.1 to about 5 parts by weight in some embodiments, and about 0.2 to about 3 parts by weight in some embodiments. For example, the metal hydroxide can account for about 0.01wt.% to about 5wt.% of the polymer composition, about 0.05wt.% to about 4wt.% in some embodiments, and about 0.1wt.% to about 2wt.% in some embodiments.

[0045] An example of a suitable metal hydroxide has the general formula M(OH) s , where s is the oxidation state (usually 1 to 3) and M is a metal such as a transition metal, an alkali metal, an alkaline earth metal or a main group metal. Examples of suitable metal hydroxides may include copper (II) hydroxide (Cu(OH)2), potassium hydroxide (KOH), sodium hydroxide (NaOH), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), aluminum hydroxide (Al(OH)2), s ) and the like. Also suitable are metal alkoxide compounds capable of forming a hydroxyl functional group in the presence of a solvent (e.g. water). Such compounds may have the general formula M(OR) s , where s is the oxidation state (usually 1 to 3), M is a metal, and R is an alkyl group. Examples of such metal alkoxides may include copper(II) ethoxide (Cu 2+ (CH3CH2O - )2), Potassium ethoxide (K + (CH3CH2O - ))、Sodium ethoxide (Na + (CH3CH2O - ))、Ethoxymagnesium (Mg 2+ (CH3CH2O - )2) Calcium ethoxide (Ca 2+ (CH3CH2O - )2) etc.; Aluminum ethoxide (Al 3+ (CH3CH2O - )3) etc. In certain embodiments, the metal hydroxide may be in the form of metal hydroxide particles. For example, the particles may include at least one metal hydroxide having the general formula Al(OH) a O bAluminum hydroxide, wherein 0≦a≦3 (e.g., 1) and b=(3-a) / 2. For example, in one specific embodiment, the particles exhibit a boehmite crystalline phase, and the aluminum hydroxide has the chemical formula AlO(OH) ("aluminum oxide hydroxide"). The metal hydroxide particles can be needle-shaped, elliptical, flaky, spherical, etc. In any case, the median particle size (D50) of the particles is typically from about 50 to about 800 nanometers, in some embodiments from about 150 to about 700 nanometers, and in some embodiments from about 250 to about 500 nanometers, as determined by non-invasive backscattering (NIBS) technology. If desired, the particles can also have a high specific surface area, for example, about 2 square meters per gram (m 2 / g) to about 100m 2 / g, in some embodiments about 5m 2 / g to about 50m 2 / g, and in some embodiments about 10m 2 / g to about 30m 2 / g. The surface area can be determined by the physical gas adsorption (BET) method (nitrogen as adsorbed gas) according to ISO 9277:2010. The water content can also be relatively low, for example, about 5% or less, in some embodiments about 3% or less, and in some embodiments about 0.1 to about 1%, as determined according to ISO 787-2:1981.

[0046] Other components that may also be included in the composition include, for example, reinforcing fibers (e.g., glass fibers), pigments (e.g., black pigments), antioxidants, stabilizers, crosslinking agents, lubricants, impact modifiers, flow promoters, and other materials added to enhance performance and processability.

[0047] II. Melt Processing

[0048] Liquid crystal polymer and various other optional additives (e.g., thermally conductive fillers, pigments, lubricants, etc.) can be combined in a manner as known in the art. For example, the material can be supplied to a melt processing device for dispersively mixing materials simultaneously or sequentially. Batch and / or continuous melt processing techniques can be used. For example, a mixer / kneader, Banbury mixer, Farrel continuous mixer, single screw extruder, twin screw extruder, roller mill, etc. can be used to blend and melt process materials. A particularly suitable melt processing device is a co-rotating twin screw extruder (e.g., Leistritz co-rotating fully meshing twin screw extruder). Such an extruder may include a feed port and a vent, and provide high-intensity distribution and dispersed mixing. For example, the components can be fed to the same or different feed ports of a twin screw extruder and the components can be melt blended to form a substantially uniform molten mixture. Melt blending can occur under high shear / pressure and heat to ensure sufficient dispersion. For example, melt processing may occur at a temperature of about 150° C. to about 450° C., and in some embodiments, at a temperature of about 250° C. to about 400° C. Likewise, the apparent shear rate during melt processing may be about 100 seconds. -1 to about 10,000 seconds -1 and in some embodiments within about 500 seconds. -1 to about 1,500 seconds -1 Of course, other variables, such as residence time during melt processing, which is inversely proportional to throughput rate, can also be controlled to achieve the desired uniformity.

[0049] If desired, one or more distribution and / or dispersive mixing elements may be used in the mixing section of the melt processing unit. Suitable distribution mixers may include, for example, Saxon, Dulmage, Cavity Transfer mixers, etc. Similarly, suitable dispersive mixers may include Blister rings, Leroy / Maddock, CRD mixers, etc. As is well known in the art, mixing can further improve aggressiveness by using pins that can produce folding and redirection of polymer melts in the barrel, such as those used for Buss Kneader extruders, cavity transfer mixers, and Vortex Intermeshing Pin mixers. The speed of the screw may also be controlled to improve the properties of the composition. For example, the screw speed may be about 400 rpm or less, in one embodiment, such as between about 200 rpm and about 350 rpm, or between about 225 rpm and about 325 rpm. In one embodiment, the compounding conditions may be balanced to provide a polymer composition that exhibits improved performance. For example, the compounding conditions may include a screw design to provide a mild, moderate, or aggressive screw condition. For example, a system may have a mildly aggressive screw design where the screw has a single melting section on the downstream half of the screw designed to achieve mild melting and distributive melt homogenization. A moderately aggressive screw design may have a stronger melting section upstream of the filler feed barrel that is more concentrated on stronger dispersing elements to achieve uniform melting. In addition, the moderately aggressive screw design may have another mild mixing section downstream to mix the filler. This section, while weaker, still increases the shear strength of the screw, making it stronger overall than the mildly aggressive design. A highly aggressive screw design may have the strongest shear strength of the three. The main melting section may consist of a long series of highly dispersive kneading blocks. The downstream mixing section may use a mix of distributing and dense dispersing elements to achieve uniform dispersion of all types of fillers. The shear strength of the highly aggressive screw design may be significantly higher than the other two designs. In one embodiment, the system may include a moderate to aggressive screw design with a relatively mild screw speed (eg, between about 200 rpm and about 300 rpm).

[0050] III. Busbar

[0051] A variety of busbar configurations can be formed using the polymer compositions described herein. For example, the busbar can be used in a battery assembly that includes a first battery having a first terminal (e.g., a positive terminal) and a second battery having a second terminal (e.g., a positive terminal or a negative terminal). The first terminal and the second terminal of the battery can be connected together using a busbar that includes an electrical conductor and an insulating portion. The insulating portion can be formed from the polymer composition of the present invention.

[0052] Reference Figure 1 , shows an embodiment of a busbar 10, which includes an electrical conductor 12. The electrical conductor 12 includes a conductive material 18, such as copper, aluminum, aluminum alloy, etc., and can generally be in the form of a solid rod, a hollow tube, etc. The busbar 10 includes a connector portion 14 at both ends, and the connector portion 14 is configured to match the corresponding terminals of two or more batteries. An insulating portion 16 (e.g., a coating material or a molding material) including a polymer composition as described herein can cover a portion of the conductive material of the electrical conductor 12. In order to form the busbar 10, the insulating portion 16 can be applied to the surface of the conductive material 18. For example, a rod or tube of the conductive material 18 can be inserted into a preformed tube of the insulating coating 16, such as an extruded tube that is sized and cut to the correct proportions, and then the busbar 10 can be formed into any suitable form. In another embodiment, the insulating coating can be applied to the surface of the molten conductive material 18 and can be solidified on the surface of the conductive material in the applied area.

[0053] Figure 2 Another embodiment of a busbar 20 is shown, which may include an insulating portion in the form of a coating disposed on the conductor. In this embodiment, the busbar 20 includes a tubular conductor covered with an insulating coating 26 along its length, and the insulating coating 26 may include the polymer composition described. The busbar 20 may also include connector portions 24 located at both ends, and the connector portions 24 are configured to connect to receive battery terminals.

[0054] Figure 3 to Figure 4 A portion of a busbar 30 that may include a high surface area insulating portion is shown. More specifically, an insulating portion 36 is provided on an electrical conductor 38, which is in the form of a corrugated tube, on which peaks 31 and valleys 32 are alternately formed. The insulating portion 36 may comprise a polymer composition of the present invention. If desired, the inner diameter of the valley 32 is slightly larger than the outer diameter of the conductor 38, and the peak 31 may have a space 33 between the conductor 38 and the wall of the peak 31. In one embodiment, the peak 31 may include ventilation holes 34 at certain locations. The busbar 30 also includes a terminal 33 located at the end of the conductor 38, the terminal 33 including a plate 33a and a hole 33b for matching with a battery. In one embodiment, the insulating portion 36 may include a cut 39 extending axially over its entire length, so that it can be opened circumferentially. Therefore, the conductor 38 can be inserted into the opened insulating portion 36. Optionally, in order to prevent the conductor 38 from slipping in the insulating portion 36, a heat-resistant tape 35 can be wrapped around the end of the conductor 38.

[0055] The insulating part of the busbar can be formed by a polymer composition using various different technologies. Suitable technologies may include, for example, injection molding, low-pressure injection molding, extrusion compression molding, gas injection molding, foam injection molding, low-pressure gas injection molding, low-pressure foam injection molding, gas extrusion compression molding, foam extrusion compression molding, extrusion molding, foam extrusion molding, compression molding, foam compression molding, gas compression molding, etc. For example, an injection molding system may be used, which includes a mold into which the polymer composition can be injected. The time in the syringe may be controlled and optimized so that the polymer matrix is ​​not pre-cured. When the cycle time is reached and the barrel is full of discharge, the composition may be injected into the mold cavity using a piston. A compression molding system may also be used. As with injection molding, the polymer composition may be formed into a desired article and may also be carried out in a mold. The composition may be placed in a compression mold using any known technology (e.g., by being picked up by an automatic robot arm). The temperature of the mold may be maintained at or above the curing temperature of the polymer composition and may continue for a desired period of time to allow curing. Subsequently, the molded product may be cured by introducing it to a temperature below the melting temperature. The resulting product may be demoulded. The cycle time of each molding process can be adjusted to suit the polymer composition to achieve adequate bonding and increase the productivity of the overall process.

[0056] As previously mentioned, busbars are particularly useful for use in electric vehicles. Figure 5 , for example, one embodiment of an electric vehicle 112 including a powertrain 110 is shown. The powertrain 110 includes one or more electric machines 114 connected to a transmission 116, which in turn is mechanically connected to the drive shaft 110 and wheels 122. Although by no means required, the transmission 116 in this particular embodiment is also connected to an engine 118. The electric machine 114 can be capable of operating as a motor or a generator to provide propulsion and deceleration capabilities. The powertrain 110 also includes a propulsion source, such as a battery assembly 124, which stores and provides energy for use by the electric machine 114. The battery assembly 124 typically provides a high voltage current output (e.g., a voltage of about 400 volts to about 800 volts direct current) from one or more battery cell arrays, which may include one or more battery cells.

[0057] The powertrain 110 also includes at least one power electronics module 126, which is connected to the battery assembly 124 and may include a power converter (e.g., an inverter, a rectifier, a voltage converter, etc., and a combination thereof). The power electronics module 126 is generally electrically connected to the motor 114 and provides the ability to bidirectionally transmit electrical energy between the battery assembly 124 and the motor 114. For example, the battery assembly 124 may provide a DC voltage, while the motor 114 may require a three-phase AC voltage to operate. The power electronics module 126 may convert the DC voltage into a three-phase AC voltage according to the needs of the motor 114. In regenerative mode, the power electronics module 126 may convert the three-phase AC voltage from the motor 114 as a generator into the DC voltage required by the battery assembly 124. The description herein is also applicable to pure electric vehicles. The battery assembly 124 may also provide energy for other vehicle electrical systems. For example, the powertrain may employ a DC / DC converter module 128, which converts the high-voltage DC output from the battery assembly 124 into a low-voltage DC supply compatible with other vehicle loads (e.g., a compressor and an electric heater). In a typical vehicle, the low voltage system is electrically connected to an auxiliary battery 130 (e.g., a 12V battery). There may also be a battery energy control module (BECM) 133 in communication with the battery assembly 124, which acts as a controller for the battery assembly 124 and may include an electronic monitoring system that manages the temperature and state of charge of each battery cell. The battery assembly 124 may also have a temperature sensor 131, such as a thermistor or other thermometer. The temperature sensor 131 may communicate with the BECM 133 to provide temperature data about the battery assembly 124. The temperature sensor 131 may also be located on or near a battery cell within the traction battery 124. It is also contemplated that more than one temperature sensor 131 may be used to monitor the temperature of a battery cell.

[0058] In certain embodiments, the battery assembly 124 can be charged by an external power source 136 (e.g., an electrical outlet). The external power source 136 can be electrically connected to an electric vehicle supply equipment (EVSE) that regulates and manages the transfer of electrical energy between the power source 36 and the vehicle 112. The EVSE 138 can have a charging connector 140 for plugging into a charging port 134 of the vehicle 112. The charging port 134 can be any type of port configured to transfer power from the EVSE 138 to the vehicle 112 and can be electrically connected to a charger or an onboard power conversion module 132. The power conversion module 132 can regulate the power supplied from the EVSE 138 to provide the appropriate voltage and current levels to the battery assembly 124. The power conversion module 132 can interact with the EVSE 138 to coordinate the delivery of power to the vehicle 112.

[0059] Refer again Figure 5, bus bars (not shown) may be used to electrically connect the cells of the battery assembly 124. Figure 6 For example, the battery assembly 124 may include a plurality of battery cells 158. The battery cells 158 may be stacked side by side to form a battery cell group, sometimes referred to as a battery array. In one embodiment, the battery cells 158 are prismatic lithium-ion batteries. However, battery cells having other geometries (cylindrical, pouch, etc.) and / or chemical compositions (nickel metal hydride, lead acid, etc.) may alternatively be used within the scope of the present disclosure. Each battery cell 158 includes a positive terminal (represented by the symbol (+)) and a negative terminal (represented by the symbol (-)). The battery cells 158 are arranged so that the terminals of each battery cell 158 are adjacent to the terminals of an adjacent battery cell 158 of opposite polarity. As used herein, the terms "battery," "cell," and "battery cell" are used interchangeably to refer to any type of single battery element used in a battery system. The batteries described herein generally include lithium-based batteries, but may include a variety of chemistries and configurations, including iron phosphate, metal oxide, lithium-ion polymer, nickel metal hydride, nickel cadmium, nickel-based batteries (hydrogen, zinc, cadmium, etc.), and any other battery type compatible with electric vehicles. For example, some embodiments may use batteries from The 6831NCR 18650 battery cell of FIG. 1 is a 6831NCR 18650 battery cell, or some variant of the 18650 form-factor that is 6.5 cm x 1.8 cm and about 45 g.

[0060] As is known in the art, the busbars connect the battery cells (e.g. Figure 6 ) may vary. Figure 7 , for example, shows a top isometric view 900 and a bottom isometric view 902 of a plate bus bar 906 aligned with a plurality of battery cells 904 arranged in a plurality of rows. Figure 6As shown, a plurality of battery cells 904 are arranged into multiple groups of adjacent rows. The cutout portion 901 of the busbar 906 may include a recess that allows each battery cell 904 to be placed in a portion of the cutout 901. In these embodiments, the busbar 906 may be used as a template for placing each battery cell so that each battery cell is uniform in each prepared battery assembly. During the manufacturing process, the busbar 906 can also keep each battery cell 904 in position, and any insulation pad or injection shell that can be formed by the polymer composition described herein can be added without causing each battery cell to deviate from the position. As shown in view 902, the center piece 910 of each cutout can be in spring contact with the bottom surface of each of the battery terminals without any welding or other type of mechanical connection. The busbar 906 may include an insulator 912 located on / around each contact area of ​​each cutout portion 901, which can hold the end of each battery cell 904. In some embodiments, the insulator 912 can extend over the busbar 906 and exceed the cutout portion 901.

[0061] Figure 8 A bottom isometric view 1002 of a busbar 906 matching a battery assembly with a housing 1004 is shown. If desired, the housing 1004 may be formed from a polymer composition described herein. The housing 1004 may be injected into an injection mold and molded to fit and hold the battery cell 904. In one embodiment, the housing 1004 may be applied so that it is flush with the top of each battery cell 904. In some embodiments, the housing 1004 does not cover the top or bottom of each battery cell 904. Instead, these areas of each battery cell 904 are exposed so that electrical connections can be made between each battery cell 904 and the busbar 906 after the housing is applied. In other embodiments (not shown), the housing 1004 does not extend all the way to the top terminal and / or bottom terminal of the battery assembly. In some embodiments, the exposed portion of each battery cell 904 may be between 1.0 mm and 15.0 mm. The amount of exposure of each battery cell 904 may be different between the top and bottom of each battery cell 904. By leaving a portion of each battery cell 904 exposed, certain types of electrical connections to each battery cell may be more easily applied.

[0062] In some embodiments, the busbar 906 may be placed in the housing 1004, and the housing 1004 may cover the busbar connection to the battery cell 904. In one embodiment, the battery assembly may include a polymer composition as described herein injected into the housing 1004, and a solid-state battery assembly may be formed. In some embodiments, the busbar 916 may be fixed to the bottom of the battery assembly by the housing 1004 or by other mechanical means (e.g., screws or adhesives).

[0063] Figures 7 and 8A plate bus bar 906 defined in a continuous plane is shown that contacts each battery in the depicted portion of the battery assembly. However, other embodiments need not be so limited. For example, Figure 8 Another embodiment of a busbar 914, 916 as described herein that may be used in a battery assembly is shown. As shown, the battery assembly may include a plurality of busbars 914, 916 in the form of conductive bars of unique lengths, the busbars 914, 916 including an insulator covering one or more portions of the busbars. The busbars may be of any suitable geometry, such as a single linear busbar 914, or a Z-shaped busbar 916, or a three-dimensional geometry as discussed previously. For example, a linear busbar 914 may be connected to each battery cell 904 of a single row of battery assemblies, while a Z-shaped busbar 916 may provide connection of the busbar 914 to other electrical components of the system, such as an inverter. As shown in FIG. Figures 8 to 9 As shown in , the battery assembly may also include one or more connectors 908, such as those described above, for electrically connecting the battery assembly to other components of the electric vehicle, such as a power electronics module, for example Figure 5 A power electronics module 126 , a DC / DC converter module 128 , and / or a power conversion module 132 are shown.

[0064] Fig.10 Another embodiment of a battery assembly in which the polymer composition of the present invention can be used is shown. As shown, the battery assembly includes a plurality of battery cells 301, an end plate 306, a side plate 307, and a wiring harness assembly 308 arranged in sequence along the longitudinal direction Y. The battery assembly may also include two electrode terminals protruding outward from the top thereof, namely a positive terminal T1 and a negative terminal T2. In one embodiment, as shown, the end plate 306 and the side plate 307 may be connected together to form a rectangular frame. The battery cell 301 may be fixed by joining with a frame. The busbar assembly is fixed with a wiring harness assembly 308 and includes a plurality of busbars 302, 303, and 305 in the form of flat plates. If desired, busbars 302, 303, and / or 305 may include the polymer composition described herein, such as a coating as a part of the busbar or as a separator between the busbar and another component.

[0065] The present invention may be better understood with reference to the following examples.

[0066] Test Method

[0067] Thermal conductivity: As known in the art, the thermal diffusivity of the sample in various directions (in-plane, across-plane, through-plane) can be preliminarily determined based on the laser flash method according to ASTM E 1461-13 (2022). The thermal conductivity (in-plane, across-plane, and through-plane) can then be calculated according to the following formula: Thermal conductivity (W / m*K) = Cp*ρ*α, where Cp is the specific heat capacity of the sample (J / kgK), ρ is the intrinsic density of the sample (kg / m) measured according to ISO 11831-1:2019 (Method A) 3 ), α is the measured thermal diffusivity (m 2 / s).

[0068] Melt viscosity: can be based on ISO 11443:2021, in 1000s -1 Melt viscosity (Pa-s) is measured using a Dynisco LCR7001 capillary rheometer at a shear rate of 1.5 %. The rheometer hole (die) may have a diameter of 1 mm, a length of 20 mm, an L / D ratio of 20.1, and an angle of incidence of 180°. The diameter of the barrel may be 9.55 mm + 0.005 mm, and the length of the rod may be 233.4 mm. The melt viscosity is typically measured at a temperature 15° C. above the melting temperature of the polymer and / or composition, for example, about 350° C.

[0069] Melting temperature: The melting temperature (Tm) can be determined by differential scanning calorimetry (DSC) as known in the art. The melting temperature is the differential scanning calorimetry (DSC) peak melting temperature as determined by ISO test number 11357-3:2018. Under the DSC procedure, as described in ISO standard 10350, the sample is heated and cooled at 20°C per minute using DSC measurements performed on a TAQ2000 instrument.

[0070] Tensile modulus, tensile stress at break, and tensile strain at break: Tensile properties can be tested according to ISO 527:2019 (technically equivalent to ASTM D638-14). Modulus and strength measurements can be performed on the same test strip sample with a length of 80 mm, a thickness of 10 mm, and a width of 4 mm. The test temperature can be 23°C, and the test speed for tensile strength and tensile strain at break can be 5 mm / min, and the test speed for tensile modulus can be 1 mm / min.

[0071] Flexural modulus and flexural stress: Flexural properties may be tested according to ISO 178:2019 (technically equivalent to ASTM D790-10). The test may be performed over a 64 mm support span. The test may be performed on the center portion of an uncut ISO 3167 multipurpose bar. The test temperature may be 23°C and the test speed may be 2 mm / min.

[0072] Charpy impact strength: Charpy properties can be tested according to ISO 179-1:2010 (technically equivalent to ASTM D256-10, method B). The test can be performed using a Type 1 specimen size (length 80 mm, width 10 mm and thickness 4 mm). The specimens can be cut from the center of the multi-purpose bar using a single tooth milling machine. The test temperature can be 23°C. For "notched" impact strength, the test can be performed using a Type A notch (base circle radius of 0.25 mm) and a Type 1 specimen size (length 80 mm, width 10 mm and thickness 4 mm).

[0073] Comparative Tracking Index (CTI): The Comparative Tracking Index (CTI) can be determined in accordance with International Standard IEC 60112-2003 to provide a quantitative indication of the performance of a composition as an electrical insulating material under conditions of moisture and / or contamination. In determining the CTI rating of a composition, two electrodes are placed on a formed test specimen. A voltage difference is then established between the electrodes when a 0.1% aqueous solution of ammonium chloride is dripped onto the test specimen. The maximum voltage at which five (5) specimens do not fail during a test period of 50 drops is determined. The test voltage range is 100 to 600V, in increments of 25V. The value of the voltage at which fifty (50) drops of electrolyte result in failure is the "Comparative Tracking Index". This value provides an indication of the relative tracking resistance of the material. According to UL746A, a nominal part thickness of 3mm is considered representative of performance at other thicknesses.

[0074] Examples 1 to 2

[0075] The following two (2) commercially available samples were compounded and injection molded for use in busbars.

[0076]

[0077] LCP 1 is formed from 73% HBA and 27% HNA. LCP 2 is believed to be formed from 50% HBA, 25% BP and 25% TA. The samples were tested for mechanical properties, thermal properties and thermal conductivity as described herein. The results are as follows.

[0078] Example 1 Example 2 Tensile modulus (MPa) 9,887 14,000 Tensile strength(MPa) 50 143 Tensile elongation (%) 0.86 2.7 Flexural modulus (MPa) 13,500 13,000 Bending strength(MPa) 79 160 <![CDATA[Izod impact strength (unnotched) (kJ / m 2 )]]> 7.0 29 <![CDATA[Izod impact strength (notched) (kJ / m 2 )]]> 3.6 10 DTUL(℃) 228 240 Tm(℃) 345-350 335 <![CDATA[1,000s -1 Lower melt viscosity (Pa-s)]]> 254(380℃) 42 TC, in-plane (W / mK) 9.4 2.5 TC, across the plane (W / mK) 9.0 1.0 TC, through plane (W / mK) 1.9 0.6 Dielectric strength (kV / mm) - 30 CTI(V) 175

[0079] Example 3

[0080] The following samples were compounded and injection molded for busbars.

[0081]

[0082] LCP 3 is formed from 43% HBA, 20% NDA, 9% TA and 28% HQ. The samples were tested for mechanical properties, thermal properties and thermal conductivity as described herein. The results are as follows.

[0083] Example 3 Tensile modulus (MPa) 10,000 Tensile strength(MPa) 82 Tensile elongation (%) 2.1 Flexural modulus (MPa) 10,000 Bending strength(MPa) 109 <![CDATA[Izod impact strength (unnotched) (kJ / m 2 )]]> 13 <![CDATA[Izod impact strength (notched) (kJ / m 2 )]]> - DTUL(℃) 261 <![CDATA[1,000s -1 Lower melt viscosity (MPa-s)]]> 43.6 Tm(℃) 315 TC, in-plane (W / mK) 4.8 TC, across the plane (W / mK) 3.4 TC, through plane (W / mK) 0.8 Dielectric strength (kV / mm) 41 CTI(V) 250

[0084] Without departing from the spirit and scope of the present invention, those of ordinary skill in the art may make these and other modifications and variations to the present invention. In addition, it should be understood that the aspects of each embodiment may be interchangeable as a whole or in part. In addition, those of ordinary skill in the art will appreciate that the foregoing description is exemplary only and is not intended to limit the present invention as further described in the appended claims.

Claims

1. A busbar comprising an insulating portion covering at least a portion of an electrical conductor, wherein: The insulating portion comprises a polymer composition comprising a polymer matrix comprising a thermotropic liquid crystal polymer, further wherein the polymer composition exhibits a thermal conductivity of 1000 s at 1,000 s according to ISO 11443:2021. -1 The invention also provides a melt viscosity of about 300 Pa-s or less measured at a shear rate of about 1000 Pa and a temperature about 15°C higher than the melting temperature of the composition, and a deflection temperature under load of about 170°C or more measured under a load of 1.8 MPa according to ISO 75:2013.

2. The busbar of claim 1, wherein the polymer composition exhibits a melting temperature of about 250°C to about 440°C.

3. The busbar of claim 1, wherein the thermotropic liquid crystal polymer comprises repeating units derived from one or more aromatic dicarboxylic acids, one or more aromatic hydroxycarboxylic acids, or a combination thereof. 4 . The busbar according to claim 3 , wherein the aromatic hydroxycarboxylic acid comprises 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, or a combination thereof. 5 . The busbar according to claim 4 , wherein the aromatic dicarboxylic acid comprises terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, or a combination thereof.

6. The busbar of claim 3, wherein the liquid crystal polymer further comprises repeating units derived from one or more aromatic diols. 7 . The busbar of claim 6 , wherein the aromatic diol comprises hydroquinone, 4,4′-biphenol, or a combination thereof.

8. The busbar of claim 1, wherein the thermotropic liquid crystal polymer is fully aromatic.

9. The busbar according to claim 1, wherein the thermotropic liquid crystal polymer includes a repeating unit derived from naphthalenehydroxycarboxylic acid and / or naphthalene dicarboxylic acid in an amount of about 10 mol.% or more.

10. The busbar of claim 1, wherein the polymer composition exhibits an in-plane thermal conductivity of about 2 W / mK or more as measured according to ASTM E 1461-13 (2022).

11. The busbar of claim 1, wherein the polymer composition exhibits a trans-plane thermal conductivity of about 0.8 W / mK or more as measured according to ASTM E 1461-13 (2022).

12. The busbar of claim 1, wherein the polymer composition exhibits an in-plane thermal conductivity of about 4 W / mK to about 8 W / mK measured according to ASTM E 1461-13 (2022).

13. The busbar of claim 1, wherein the polymer composition exhibits a dielectric strength of about 10 kV / mm or more as measured according to IEC 60234-1:2013.

14. The busbar of claim 1, wherein the polymer composition further comprises a thermally conductive filler.

15. The busbar of claim 14, wherein the thermally conductive filler comprises mineral particles.

16. The busbar of claim 15, wherein the mineral particles comprise talc.

17. The busbar of claim 15, wherein the mineral particles are present in an amount of about 70 to about 250 parts by weight per 100 parts by weight of the polymer matrix.

18. The busbar of claim 15, wherein the mineral particles have a median diameter of about 1 micron to about 25 microns and a specific surface area of ​​about 1 m2 as measured according to DIN 66131:1993. 2 / g to about 50m 2 / g, and / or a water content of about 5% or less as measured at a temperature of 105°C according to ISO 787-2:1981.

19. The busbar of claim 14, wherein the thermally conductive filler comprises mineral fibers.

20. The busbar of claim 19, wherein the mineral fibers comprise wollastonite.

21. The busbar of claim 19, wherein the mineral particles are present in an amount of about 10 to about 150 parts by weight per 100 parts by weight of the polymer matrix.

22. The busbar of claim 1, wherein the polymer composition does not contain a filler having an intrinsic thermal conductivity of 100 W / mK or greater.

23. The busbar of claim 1, wherein the polymer composition exhibits a comparative tracking index of about 170 volts or more measured at 3 millimeters thickness according to IEC 60112:2003.

24. A battery assembly comprising a first battery cell and a second battery cell, wherein the bus bar according to claim 1 connects the first battery cell to the second battery cell.

25. An electric vehicle comprising the battery assembly according to claim 24.

26. The electric vehicle of claim 25, comprising a powertrain including at least one electric propulsion source and a transmission connected to the propulsion source via at least one power electronics module.

27. The electric vehicle of claim 26, wherein the propulsion source comprises a battery assembly.

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