Battery insulator

Abstract

The invention relates to an insulating sheet suitable for use in battery stacks, in particular for automotive applications.

Description

[0001] Cross-references to related patent applications

[0002] This application claims priority to PCT / CN 2022 / 084165, filed on March 30, 2022, and the entire contents of this application are incorporated by reference into this application for all purposes. Technical Field

[0003] The present invention relates to an insulation sheet suitable for use in battery stacks, in particular for automotive applications. Background Art

[0004] Nowadays, electric vehicles are becoming popular, and automobile manufacturers require lithium batteries with increased and faster charging capacity.

[0005] At the same time, lithium battery safety is more necessary than ever.

[0006] In fact, when charging a battery with a known amount of energy, you cannot deliver exactly the same amount of energy in the form of electrical energy during discharge. There are always losses, where energy is released to the environment in the form of heat.

[0007] To prevent the massive heat transfer between a failed battery cell and its neighboring battery cells or other modules, insulator materials need to be installed, which can be difficult given the small amount of space available in a battery stack.

[0008] Plastic materials have been disclosed for use in manufacturing fuel cell components, such as end plates and housings, see, for example, JP 2001-236982 (in the name of Toray Ind.), US 2002 / 182470 (in the name of Ticona LLC.), and US 2003 / 0152819 (in the name of Panasonic Intellectual Property Management CO., Ltd.). Summary of the invention

[0009] In this framework, the applicant believes that as lithium batteries become more efficient, the requirements for insulators and insulating materials are becoming increasingly higher.

[0010] The problem faced by the Applicant was therefore that of providing an insulating material suitable for batteries, easy to manufacture on an industrial scale and having a very small thickness.

[0011] Thus, in a first aspect, the present invention relates to a sheet [sheet (P)] having a thickness equal to or less than 3 mm and made of at least one liquid crystal polymer [polymer LCP].

[0012] Preferably, the sheet (P) is made of a composition comprising:

[0013] - at least one liquid crystal polymer [polymer LCP] and

[0014] - from about 5 wt. % to about 50 wt. % of reinforcing fillers.

[0015] In a further aspect, the invention relates to a battery system (1) comprising:

[0016] - a battery block comprising at least two adjacently stacked battery cells (2);

[0017] - a fastening member (3) for holding the at least two battery cells, comprising: (i) a pair of end plates (4), each end plate being disposed at one end of the at least two adjacently stacked battery cells, and (ii) a metal strip (5) disposed at a side wall of the battery block extending in the stacking direction of the battery cells and connected to the end plates (4) at both ends;

[0018] wherein at least one sheet (P) (6) as defined above

[0019] - applied to each of said end plates (4); and / or

[0020] - inserted between two adjacent stacked battery cells (2).

[0021] Advantageously, the sheet (P) according to the invention provides an insulating layer capable of withstanding very high temperatures (in particular 200 to 600° C. or even higher) for 30-60 minutes, allowing to delay or even prevent thermal runaway from a faulty cell to its neighbours or other modules.

[0022] In a further aspect, the present invention relates to the use of said sheet (P) as defined above for manufacturing a battery system comprising a pair of end plates, wherein said sheet (P) is applied to each end plate of said battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a side view of an exemplary battery system. DETAILED DESCRIPTION

[0024] In this application and the following claims:

[0025] - any description (even those relating to a specific embodiment) is applicable to and interchangeable with other embodiments of the invention;

[0026] - Any recitation of numerical ranges by endpoints herein includes all numbers contained in the recited range as well as the endpoints of that range and equivalents thereof;

[0027] - The term "alkyl" and derivative terms such as "alkoxy", "acyl" and "alkylthio" include straight chain, branched and cyclic moieties. Examples of alkyl groups are methyl, ethyl, 1-methylethyl, propyl, 1,1 dimethylethyl and cyclopropyl. Unless otherwise expressly indicated, each alkyl and aryl group may be unsubstituted or substituted with one or more substituents selected from, but not limited to, halogen, hydroxy, sulfonyl, C 1 -C 6 Alkoxy, C 1 -C 6 Alkylthio, C 1 -C 6 Acyl, formyl, cyano, C 6 -C 15 Aryloxy or C 6 -C 15 Aryl groups, provided that the substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy;

[0028] - the term "halogen" or "halo" includes fluorine, chlorine, bromine and iodine, of which fluorine is preferred;

[0029] - The term "aryl" refers to phenyl, indanyl or naphthyl. An aryl group may contain one or more alkyl groups and in this case is sometimes referred to as an "alkylaryl group"; for example, an aromatic group and two C 1 -C 6 The aryl group may also contain one or more heteroatoms (e.g., N, O, or S) and is sometimes referred to as a "heteroaryl"; these heteroaromatic rings may be fused to other aromatic systems. Such heteroaromatic rings include, but are not limited to, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, and triazinyl ring structures. The aryl or heteroaryl substituents may be unsubstituted or substituted with one or more substituents selected from, but not limited to, halogen, hydroxyl, C 1 -C 6 Alkoxy, sulfo, C 1 -C 6 Alkylthio, C 1 -C 6 Acyl, formyl, cyano, C 6 -C 15 Aryloxy or C 6 -C 15 Aryl groups, provided that the substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy;

[0030] - unless expressly stated otherwise, the "mol %" of each repeating unit is relative to the total number of moles of repeating units in the polymer; and

[0031] - The expression "derived from" means that the repeating units are formed by the polycondensation of said monomers.

[0032] Preferably, the composition comprises 50 to 90 wt.%, more preferably 55 to 88.9 wt.% and even more preferably 60 to 70 wt.% of the polymer LCP, based on the total weight of the composition.

[0033] According to a first embodiment, the polymer LCP is obtained by the polycondensation reaction of (I) terephthalic acid, (II) at least one aromatic diol, and (III) at least one aromatic dicarboxylic acid and / or hydroxycarboxylic acid.

[0034] Preferably, the (II) at least one aromatic diol is represented by a formula selected from the group consisting of:

[0035] HO-Ar 1 -OH (1)

[0036] HO-Ar 2 -T 1 -Ar 3 -OH (2)

[0037] in

[0038] Ar 1 To Ar 3 Each independently selected from C 6 -C 30 Aryl, which may be optionally substituted by one or more substituents selected from the group consisting of halogen, C 1 -C 15 Alkyl, and C 6 -C 15 aryl; and

[0039] T 1 Selected from the group consisting of: bond, O, S, -SO 2 -, -C(=O)-, and C 1 -C 15 alkyl.

[0040] More preferably, the (II) at least one aromatic diol is selected from the group consisting of 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2,5-biphenyl diol, 4,4'-biphenol, 4,4'-(propane-2,2-diyl)diphenol, 4,4'-(ethane-1,2-diyl)diphenol, 4,4'-methylenediphenol, bis(4-hydroxyphenyl)ketone, 4,4'-oxydiphenol, 4,4'-sulfonyldiphenol, 4,4'-thiodiphenol, naphthalene-2,6-diol and naphthalene-1,5-diol.

[0041] Even more preferably, the aromatic diol is 4,4'-biphenol.

[0042] Preferably, the (III) at least one aromatic dicarboxylic acid is represented by a formula selected from the group consisting of:

[0043] HOOC-Ar 1 -COOH (3)

[0044] HOOC-Ar 2 -T 2 -Ar 3 -COOH (4)

[0045] in

[0046] Ar 1 To Ar 3 are independently selected and have the meanings as defined above; and

[0047] T 2 Selected from the group consisting of: σ bond, O and S.

[0048] Preferably, the aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-oxydibenzoic acid, 4,4'-(ethylenedioxy)dibenzoic acid, 4,4'-sulfanediyldibenzoic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid and naphthalene-2,3-dicarboxylic acid.

[0049] More preferably, the aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid and naphthalene-2,3-dicarboxylic acid.

[0050] Even more preferably, the aromatic dicarboxylic acid is isophthalic acid.

[0051] Preferably, the at least one aromatic hydroxycarboxylic acid is represented by a formula selected from the group consisting of

[0052] HO-Ar 1 -COOH (5)

[0053] HO-Ar 2 -Ar 3 -COOH (6)

[0054] in

[0055] Ar 1 To Ar 3 are independently selected and have the meanings as defined above.

[0056] Preferably, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 5-hydroxy-1-naphthoic acid and 4'-hydroxy-[1,1'-biphenyl]-4-carboxylic acid.

[0057] More preferably, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid and 5-hydroxy-1-naphthoic acid.

[0058] Even more preferably, the aromatic hydroxycarboxylic acid is 4-hydroxybenzoic acid.

[0059] Preferably, the at least one aromatic dicarboxylic acid and the aromatic hydroxycarboxylic acid are free of naphthyl groups.

[0060] Preferably, the polymer LCP comprises repeating units R LCP1 To R LCP4 ,in:

[0061] The repeating unit R LCP1 It is expressed by the following formula:

[0062]

[0063] The repeating unit R LCP2 It is represented by any of the following formulas:

[0064] -[-O-Ar 1 -O-]- (2a)

[0065] -[-O-Ar 2 -T 1 -Ar 3 -O-]- (2b);

[0066] The repeating unit R LCP3 It is represented by any of the following formulas:

[0067] -[-OC-Ar 1 -CO-]- (3a)

[0068] -[-OC-Ar 2 -T 2 -Ar 3 -CO-]- (3b);

[0069] The repeating unit R LCP4 It is represented by any of the following formulas:

[0070] -[-O-Ar 1 -CO-]- (4a)

[0071] -[-O-Ar 2 -Ar 3 -CO-]- (4b);

[0072] in

[0073] Ar 1 To Ar 3 、T 1 and T 2 are independently selected and have the meanings defined above.

[0074] Those skilled in the art will recognize that the R LCP1 Formed from terephthalic acid; R according to formula (2a) and (2b) LCP2 are respectively formed by monomers according to formula (1) and (2); the R according to formula (3a) and (3b) LCP3 are respectively formed by monomers according to formula (3) and (4); and the R according to formula (4a) and (4b) LCP4 Formed from monomers according to formula (5) and (6).

[0075] Therefore, for the monomers in formulae (1) to (6), Ar 1 To Ar 3 、T 1 and T 2 The choice of repeating unit R LCP2 To R LCP4 Ar 1 To Ar 3 、T 1 and T 2 A selection was made.

[0076] Preferably, the repeating unit R LCP1 To R LCP4 They are formed by the condensation of terephthalic acid, 4,4'-biphenol, isophthalic acid and 4-hydroxybenzoic acid.

[0077] Preferably, the repeating unit RLCP1 To R LCP4 The total concentration is at least 50 mol%, at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, at least 99 mol%, or at least 99.9 mol%.

[0078] In some embodiments, the repeating unit R LCP1 The concentration of is 5 mol% to 35 mol%, preferably 10 mol% to 30 mol%.

[0079] In some embodiments, the repeating unit R LCP2 The concentration of is 5 mol% to 35 mol%, preferably 10 mol% to 30 mol%.

[0080] In some embodiments, the repeating unit R LCP3 The concentration of is 0 mol% or 1 mol% to 20 mol%. According to a preferred embodiment, the repeating unit R LCP3 The concentration is 0 mol%.

[0081] In some embodiments, the repeating unit R LCP4 The concentration of is 35 mol% to 80 mol%, preferably 40 mol% to 70 mol%, most preferably 45 mol% to 65 mol%.

[0082] In one embodiment, R LCP1 , R LCP2 and R LCP4 Derived from terephthalic acid, 4,4'-biphenol and 4-hydroxybenzoic acid respectively, wherein the concentration of each repeating unit ranges within the ranges given above.

[0083] Preferably, the polymer LCP has a melting temperature ("Tm") of at least 300° C., at least 320° C., or at least 340° C. In some embodiments, the polymer composition has a Tm of no greater than 460° C., no greater than 450° C., or no greater than 440° C. In some embodiments, the polymer composition has a Tm of 360° C. to 460° C., 380° C. to 450° C., or 400° C. to 430° C. Tm can be measured according to ASTM D3418.

[0084] The sheet (P) of the invention is advantageously manufactured starting from an LCP conforming to this first embodiment.

[0085] According to a second embodiment, the polymer LCP comprises:

[0086] - 40 to 98 mol.% of repeating units of formula (I):

[0087]

[0088] - 1 to 20 mol.% of repeating units of formula (IIa), (IIb), (IIc) and / or (IId):

[0089]

[0090]

[0091] as well as

[0092] - 1 to 12 mol.% of repeating units of formula (IIIa) and / or (IIIb):

[0093]

[0094] Based on total moles of polymer in LCP.

[0095] In some embodiments, when the polymeric LCP comprises additional repeating units, they are selected from the group consisting of:

[0096]

[0097] Each of these repeating units (IV), (V) and / or (VI) may be present in the polymer LCP in a molar amount ranging from 0.1 to 15 mol.%, for example, 0.5 to 13 mol.%, 1 to 11 mol.%, 2 to 9 mol.% or 3 to 8 mol.%, based on the total moles in the polymer LCP.

[0098] In some other embodiments, the polymeric LCP comprises additional repeating units selected from the group consisting of:

[0099]

[0100] Each of these repeating units (VII), (VIII), (IX), (X), (XI) and / or (XI) may be present in the polymer LCP in a molar amount ranging from 0.1 to 15 mol.%, e.g., 0.5 to 13 mol.%, 1 to 11 mol.%, 2 to 9 mol.% or 3 to 8 mol.%, based on the total moles in the polymer LCP.

[0101] According to this embodiment, when the polymer LCP comprises additional repeating units, they are selected from the group consisting of (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI) and (XI). The polymer LPC may comprise one, two, three, four, five, six, seven, eight or nine of these repeating units. Each of these repeating units may be present in the polymer LCP in a molar amount ranging from 0.1 to 15 mol.%, such as 0.5 to 13 mol.%, 1 to 11 mol.%, 2 to 9 mol.% or 3 to 8 mol.%, based on the total moles in the polymer LCP.

[0102] Preferably, according to this second embodiment, the polymer LCP comprises 40 to 98 mol.% of repeating units having formula (I), preferably 40 to 90 mol.%, more preferably 50 to 85 mol.% or 60 to 81 mol.% of repeating units having formula (I), based on the total moles in the polymer LCP.

[0103] The polymer LCP further comprises 1 to 22 mol.% of repeating units having formula (IIa), (IIb), (IIc) and / or (IId), preferably 5 to 21 mol.% or 10 to 20 mol.% of repeating units having formula (IIa), (IIb), (IIc) and / or (IId), based on the total moles in the polymer LCP.

[0104] The polymer LCP also contains 1 to 12 mol.% of repeating units having formula (IIIa) and / or (IIIb), preferably 2 to 12 mol.%, or 2 to 11 mol.%, or 3 to 11 mol.%, or 3 to 10 mol.%, or 4 to 9.5 mol.%, or 4.5 to 8.5 mol.% of repeating units having formula (IIIa) and / or (IIIb), based on the total moles in the polymer LCP.

[0105] In these embodiments, the polymer LCP can be made from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or a derivative, such as 6-acetoxy-2-naphthoic acid (AcHNA)), biphenol (BP) (or a derivative, such as diacetoxybiphenyl (AcBP)), hydroquinone (HQ) (or a derivative, such as diacetoxybenzene (AcHQ)), and cyclohexanedicarboxylic acid (CHDA).

[0106] CHDA monomer is typically a cis / trans isomer blend, where the cis / trans ratio can vary between 1:99 and 99:1, such as between 10:90 and 90:10.

[0107] For example, the polymer LCP may be made from hydroxy-2-naphthoic acid (HNA) (or a derivative), biphenol (BP) (or a derivative) and / or hydroquinone (HQ) (or a derivative), and cyclohexanedicarboxylic acid (CHDA).

[0108] For example, the polymer LCP can be made of only these three or four monomers. Various isomers of biphenol (BP) can be used to prepare the polymer LCP. Biphenol (BP) can be, for example, in the form of 4,4'-biphenol (4,4'-BP), 3,4'-biphenol (3,4'-BP) or 3,3'-biphenol (3,3'-BP). One or more of these isomers can be used. Preferably, at least 4,4'-biphenol is used to prepare the polymer LCP. Various isomers of hydroquinone (HQ) can also be used.

[0109] The polymer LCP according to this second embodiment may further comprise repeating units (IV), (V) and / or (VI). In these embodiments, the polymer LCP may be made from the following monomers: 2,6-naphthalenedicarboxylic acid (NDA) (or a derivative) and bibenzoic acid (BB) (or a derivative).

[0110] Various isomers of bibenzoic acid (BB) can be used to prepare the polymer LCP according to this embodiment. Bibenzoic acid (BB) can be in the form of 4,4'-bibenzoic acid (4,4'-BB) and / or 3,4'-bibenzoic acid (3,4'-BB).

[0111] In some embodiments, the polymeric LCP comprises:

[0112] - 65 to 75 mol.% of repeating units of formula (I),

[0113] - 13 to 18 mol.% of repeating units of formula (IIa), (IIb), (IIc) and / or (IId), and

[0114] -3 to 9 mol.% of repeating units of formula (IIIa) and / or (IIIb),

[0115] Optionally, at least one of the following repeating units:

[0116] -3 to 11 mol.% of repeating units of formula (IV),

[0117] -3 to 11 mol.% of repeating units of formula (V), and / or

[0118] -3 to 11 mol.% of repeating units of formula (VI).

[0119] In some preferred embodiments, the polymeric LCP comprises or consists essentially of:

[0120] - 65 to 75 mol.% of repeating units of formula (I),

[0121] - 13 to 18 mol.% of repeating units of formula (IIa), (IIb), (IIc) and / or (IId),

[0122] -3 to 9 mol.% of repeating units of formula (IIIa) and / or (IIIb), and

[0123] - optionally 3 to 11 mol. % of repeating units of formula (IV).

[0124] The polymer LCP according to this second embodiment may additionally comprise repeating units (VII), (VIII), (IX), (X), (XI) and / or (XII).

[0125] In these embodiments, the polymer LCP can be made from the following monomers: hydroxybenzoic acid (HBA) (or derivatives, such as acetoxybenzoic acid (AcHBA)), terephthalic acid (TPA) (or derivatives), isophthalic acid (IPA) (or derivatives), resorcinol (RS) (or derivatives) and / or catechol (CT) (or derivatives).

[0126] In these embodiments, the polymer LCP can be made from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives, such as 6-acetoxy-2-naphthoic acid (AcHNA)), biphenol (BP) (or derivatives, such as diacetoxybiphenyl (AcBP)), hydroquinone (HQ) (or derivatives, such as diacetoxybenzene (AcHQ)), cyclohexanedicarboxylic acid (CHDA), terephthalic acid (TPA) (or derivatives) and / or isophthalic acid (IPA) (or derivatives).

[0127] For example, polymer LCP can be made only of HNA (or derivatives), BP or (derivatives), HQ (or derivatives), CHDA (or derivatives) and TPA (or derivatives). Polymer LCP can also be made only of HNA (or derivatives), BP (or derivatives), HQ (or derivatives), CHDA (or derivatives), and IPA (or derivatives). Polymer LCP can also be made only of HNA (or derivatives), BP (or derivatives), HQ (or derivatives), CHDA (or derivatives), TPA (or derivatives) and IPA (or derivatives).

[0128] Various isomers of hydroxybenzoic acid (HBA) can be used to prepare the polymer LCP according to this embodiment. Notably, HBA can be in the form of 4-hydroxybenzoic acid (4-HBA) and / or 3-hydroxybenzoic acid (3-HBA).

[0129] In some embodiments, the polymer LCP is such that the number of moles of repeating units is as follows:

[0130] - formula (I) + (II) + (III) + (IV) + (V) + (VI) + (VII) + (VIII) + (IX) + (X) + (XI) + (XII) = 100 mol%, wherein the number of moles of repeating units of formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI) and / or (XII) is ≥ 0 mol%.

[0131] - formula (I) + (II) + (III) + (IV) + (V) + (VI) = 100 mol.%, wherein the number of moles of repeating units of formula (IV), (V) and / or (VI) is ≥ 0 mol.%, and

[0132] - formula (I) + (II) + (III) + (VII) + (VIII) + (IX) + (X) + (XI) + (XII) = 100 mol.%, wherein the molar number of repeating units of formula (VII), (VIII), (IX), (X), (XI) and / or (XII) is ≥ 0 mol.%.

[0133] In these embodiments, the polymer LCP can be made only from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives), hydroquinone (HQ) (or derivatives), cyclohexanedicarboxylic acid (CHDA) (or derivatives), 2,6-naphthalene dicarboxylic acid (NDA) (or derivatives), and bibenzoic acid (BB) (or derivatives).

[0134] For example, the polymer LCP of the present invention may be such that the number of moles of repeating units is as follows:

[0135] - formula (I) + (II) + (III) = 100 mol.%, for example, formula (I) + (IIa) + (IIIa) = 100 mol.%,

[0136] - formula (I) + (II) + (III) + (IV) = 100 mol.%, for example, formula (I) + (IIa) + (IIIa) + (IV) = 100 mol.%,

[0137] - Formula (I) + (II) + (III) + (V) = 100 mol%.

[0138] -Formula (I)+(II)+(III)+(VI)=100mol.%,

[0139] - formula (I) + (II) + (III) + (IX) = 100 mol%, or

[0140] -Formula (I) + (II) + (III) + (X) = 100 mol.%.

[0141] In some embodiments, the polymer LCP can be made only from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives), cyclohexanedicarboxylic acid (CHDA) (preferably 1,4-CHDA), and 2,6-naphthalene dicarboxylic acid (NDA) (or derivatives).

[0142] According to this second embodiment, the polymer LCP described herein has a melting temperature (Tm) above 260°C, such as in the range between 260°C and 320°C, such as between 270°C and 310°C, or between 280°C and 300°C, as determined according to ASTM D3418 using differential scanning calorimetry (DSC) (cooling, heating / cooling rate of 20°C / min).

[0143] According to this second embodiment, the polymer LCP described herein has a crystallization temperature (Tc) of less than 260°C, such as in the range of between 150°C and 260°C, such as in the range of between 155°C and 250°C, or between 160°C and 246°C, or between 160°C and 240°C, as determined according to ASTM D3418 using differential scanning calorimetry (DSC) (cooling, heating / cooling rate of 20°C / min).

[0144] According to this second embodiment, the polymer LCP has a dielectric constant Dk at 5 GHz of less than 3.5, preferably less than 3.4, or less than or equal to 3.3, as measured in the in-plane direction (5 GHz) on a 4 cm x 4 cm x 150 μm (thickness) film obtained from a "dry molded" compression molded film using a split cylindrical resonator (SCR method) according to ASTM D2520.

[0145] According to this second embodiment, the polymer LCP has a dissipation coefficient Df at 5 GHz of less than 0.0060, preferably less than 0.0058, or less than or equal to 0.0055, as measured in the in-plane direction (5 GHz) on a 4 cm x 4 cm x 150 μm (thickness) film obtained from a "dry molded" compression molded film using a split cylindrical resonator (SCR method) according to ASTM D2520.

[0146] According to this second embodiment, the polymer LCP has a dielectric constant Dk at 20 GHz of less than 3.6, preferably less than 3.5, or less than or equal to 3.4, as measured in the in-plane direction (20 GHz) on a 4 cm x 4 cm x 150 μm (thickness) film obtained from a "dry molded" compression molded film using a split cylindrical resonator (SCR method) according to ASTM D2520.

[0147] According to this second embodiment, the polymer LCP has a dissipation factor Df of less than 0.0030, preferably less than 0.0025, or less than or equal to 0.0020 at 20 GHz, as measured in the in-plane direction on a 4 cm x 4 cm x 150 μm (thickness) film obtained from a "dry molded" compression molded film using a split cylindrical resonator (SCR method) according to ASTM D2520 (20 GHz). The polymer LCP more preferably has a dissipation factor Df of 0.0010 to 0.0020 or 0.0011 to 0.0019 at 20 GHz.

[0148] According to a third embodiment, the polymer LCP comprises:

[0149] a) 40 to 98 mol.% of repeating units of formula (i):

[0150]

[0151] b) 1 to 30 mol.% of repeating units of formula (ii):

[0152]

[0153]

[0154] as well as

[0155] c) a repeating unit having two carboxyl groups of formula (iii):

[0156] - 1 to 23 mol.% of repeating units of formula (iiia):

[0157]

[0158] - 1 to 13 mol.% of repeating units of formula (iiib):

[0159]

[0160] If the polymer LCP according to this third embodiment comprises additional repeating units, these additional repeating units may be selected in the group consisting of

[0161] - repeating units of formula (VII), (VIII), (IX) and (X) as defined above. Each of such repeating units (VII) and (VIII) may be present in the polymer LCP in a molar amount ranging from 0.1 to 15 mol.%, for example 0.5 to 13 mol.%, 1 to 11 mol.%, 2 to 9 mol.% or 3 to 8 mol.%, based on the total moles in the polymer LCP. Each of such repeating units (IX) and (X) may be present in the polymer LCP in a molar amount ranging from 0.1 to 25 mol.%, for example 0.5 to 22 mol.%, 1 to 21 mol.%, 2 to 20 mol.% or 3 to 18 mol.%, based on the total moles in the polymer LCP; or

[0162] - a repeating unit of formula (I), (XI), (IIIa), (IIIb) and / or (XII) as defined above.

[0163] Each of these repeating units (I), (XI), (IIIa), (IIIb) and / or (XII) may be present in the polymer LCP in a molar amount ranging from 0.1 to 20 mol.%, for example, 0.5 to 18 mol.%, 1 to 15 mol.%, 2 to 13 mol.% or 3 to 10 mol.%, based on the total moles in the polymer LCP.

[0164] According to this third embodiment, the polymer LCP comprises 40 to 98 mol.%, preferably 40 to 90 mol.%, more preferably 50 to 85 mol.% or 60 to 81 mol.% of repeating units of formula (i), based on the total moles in the polymer LCP.

[0165] The polymer LCP further comprises 1 to 30 mol%, preferably 5 to 25 mol% or 10 to 22 mol%, based on the total moles in the polymer LCP, of repeating units of formula (ii), i.e., repeating units of formula (iia), (iib), (iic) and / or (iid).

[0166] The polymer LCP further comprises repeating units of formula (iii), i.e., repeating units of formula (iiia) and / or of formula (iiib). When the polymer LCP described herein comprises repeating units of formula (iiia), their molar ratio varies from 1 to 23 mol.%, preferably from 2 to 22 mol.%, or from 3 to 21 mol.%, or from 4 to 20 mol.%, based on the total moles in the polymer LCP. When the polymer LCP described herein comprises repeating units of formula (iiib), their molar ratio varies from 1 to 13 mol.%, preferably from 2 to 12 mol.%, or from 3 to 11 mol.%, or from 4 to 10 mol.%, based on the total moles in the polymer LCP. When the polymer LCP described herein contains both repeating units of formula (iiia) and of formula (iiib), their total molar ratio may vary from 1 to 25 mol.%, preferably from 2 to 23 mol.%, or from 3 to 21 mol.%, or from 4 to 20 mol.%, based on the total moles in the polymer LCP.

[0167] In this third embodiment, the molar ratio of 4,4'-bibenzoic acid (4,4'-BB) / 3,4'-bibenzoic acid (3,4'BB) may vary from 1:99 to 99:1, preferably from 10:90 to 90:10, even more preferably from 20:80 to 80:20.

[0168] In this third embodiment, the polymer LCP can be made from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives, such as 6-acetoxy-2-naphthoic acid (AcHNA)), biphenol (BP) (or derivatives, such as diacetoxybiphenyl (AcBP)), hydroquinone (HQ) (or derivatives, such as diacetoxybenzene (AcHQ)), and biphenylcarboxylic acid (BB) (or derivatives). Various isomers of biphenylcarboxylic acid (BB) can be used to prepare the polymer LCP according to this embodiment. Biphenylcarboxylic acid (BB) can be in the form of 4,4'-biphenylcarboxylic acid (4,4'-BB) and / or 3,4'-biphenylcarboxylic acid (3,4'-BB). For example, the polymer LCP can be made from hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives) and / or hydroquinone (HQ) (or derivatives), and 4,4'-biphenylcarboxylic acid (4,4'-BB). Polymer LCP can also be made of hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives) and / or hydroquinone (HQ) (or derivatives), and 3,4'-biphenylcarboxylic acid (3,4'-BB). Polymer LCP can also include a combination of 3,4'-BB and 4,4'-BB, for example, polymer LCP can be made of hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives) and / or hydroquinone (HQ) (or derivatives), 3,4'-biphenylcarboxylic acid (3,4'-BB) and 4,4'-biphenylcarboxylic acid (4,4'-BB). For example, polymer LCP can be made of only these three, four or five monomers. Various isomers of biphenol (BP) can be used to prepare polymer LCP according to this embodiment. Biphenol (BP) can be, for example, in the form of 4,4'-biphenol (4,4'-BP), 3,4'-biphenol (3,4'-BP) or 3,3'-biphenol (3,3'-BP). One or more of these isomers can be used. Preferably, at least 4,4'-biphenol is used to prepare the polymer LCP according to this embodiment. Various isomers of hydroquinone (HQ) can also be used.

[0169] The polymer LCP according to the third embodiment may additionally include repeating units (VII), (VIII), (IX) and / or (X) as defined above. In these embodiments, the polymer LCP may be made from the following monomers: hydroxybenzoic acid (HBA) (or derivatives, such as acetoxybenzoic acid (AcHBA)), terephthalic acid (TPA) (or derivatives), isophthalic acid (IPA) (or derivatives). Various isomers of hydroxybenzoic acid (HBA) may be used to prepare the polymer LCP. Notably, HBA may be in the form of 4-hydroxybenzoic acid (4-HBA) and / or 3-hydroxybenzoic acid (3-HBA).

[0170] According to this embodiment, the polymer LCP is prepared from TPA (or a derivative) in addition to HNA, BP, and BB (or their derivatives).

[0171] Preferably, the polymer LCP according to this third embodiment comprises or consists essentially of:

[0172] - 50 to 80 mol.% of repeating units of formula (i),

[0173] -9 to 25 mol.% of repeating units of formula (ii), and

[0174] -2 to 12 mol.% of repeating units having the formula (iiib).

[0175] Alternatively, in this third embodiment, the polymer LCP comprises or consists essentially of:

[0176] - 50 to 80 mol.% of repeating units of formula (i),

[0177] -9 to 25 mol.% of repeating units of formula (ii), and

[0178] -2 to 21 mol.% of repeating units having the formula (iiia).

[0179] Still alternatively, the polymer LCP of the third embodiment comprises or consists essentially of:

[0180] - 50 to 80 mol.% of repeating units of formula (i),

[0181] -9 to 25 mol.% of repeating units of formula (ii),

[0182] -2 to 15 mol.% of repeating units of formula (iiia), and

[0183] -2 to 11 mol.% of repeating units having the formula (iiib).

[0184] The polymer LCP may further comprise repeating units (I), (XI), (IIIa), (IIIb) and / or (XII). According to an alternative, the polymer LCP may be made from the following monomers: cyclohexanedicarboxylic acid (CHDA), preferably 1,4-CHDA, 2,6-naphthalene dicarboxylic acid (NDA) (or derivatives), resorcinol (RS) (or derivatives) and / or catechol (CT) (or derivatives). Alternatively, the polymer LCP may be made from the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives, such as 6-acetoxy-2-naphthoic acid (AcHNA)), biphenol (BP) (or derivatives, such as diacetoxybiphenyl (AcBP)), terephthalic acid (TPA) (or derivatives), and biphenylcarboxylic acid (BB). For example, the polymer LCP may be made only from HNA (or derivatives), BP or (derivatives), TPA (or derivatives) and BB (or derivatives). The polymer LCP can also be made of only HNA (or derivatives), BP (or derivatives), CHDA (or derivatives), HNA (or derivatives), TPA (or derivatives) and BB (or derivatives). The polymer LCP can also be made of only HNA (or derivatives), BP (or derivatives), HQ (or derivatives), and BB (or derivatives) (e.g., 4,4'-BB, 3,4'-BB or a combination of the two, preferably 3,4'-BB).

[0185] In some embodiments, the polymer LCP is such that the number of moles of repeating units is as follows:

[0186] - formula (i) + (ii) + (iii) + (VII) + (VIII) + (IX) + (X) + (I) + (XI) + (IIIa) + (IIIb) + (XII) = 100 mol%, wherein the number of moles of repeating units of formula (VII), (VIII), (IX), (X), (I), (XI), (IIIa), (IIIb) and / or (XII) is ≥ 0 mol%.

[0187] - formula (i) + (ii) + (iii) + (VII) + (VIII) + (IX) = 100 mol.%, wherein the number of moles of repeating units of formula (VII), (VIII) and / or (IX) is ≥ 0 mol.%, and

[0188] - formula (i) + (ii) + (iii) + (X) + (I) + (XI) + (IIIa) + (IIIb) + (XII) = 100 mol.%, wherein the number of moles of repeating units of formula (X), (I), (XI), (IIIa), (IIIb) and / or (XII) is ≥ 0 mol.%.

[0189] In these embodiments, the polymer LCP can be made from only the following monomers: 6-hydroxy-2-naphthoic acid (HNA) (or derivatives), biphenol (BP) (or derivatives), hydroquinone (HQ) (or derivatives), bibenzoic acid (BB) (or derivatives), hydroxybenzoic acid (HBA) (or derivatives, such as acetoxybenzoic acid (AcHBA)) (such as 4-hydroxybenzoic acid (4-HBA) and / or 3-hydroxybenzoic acid (3-HBA)), and bibenzoic acid (BB) (or derivatives).

[0190] For example, the polymer LCP of the third embodiment may be such that the number of moles of the repeating unit is as follows:

[0191] - formula (i) + (ii) + (iii) = 100 mol.%, for example, formula (i) + (iia) + (iiia) = 100 mol.%, or formula (i) + (iia) + (iiib) = 100 mol.%

[0192] - formula (i) + (ii) + (iii) + (X) = 100 mol%. For example, formula (i) + (iia) + (iiia) + (X) = 100 mol%. or formula (i) + (iia) + (iiib) + (X) = 100 mol%.

[0193] -Formula (i)+(ii)+(iii)+(VII)=100mol.%,

[0194] -Formula (i)+(ii)+(iii)+(VIII)=100mol.%,

[0195] - formula (i) + (ii) + (iii) + (IIIa) = 100 mol%, or

[0196] -Formula (i)+(ii)+(iii)+(IIIb)=100 mol.%.

[0197] The polymer LCP according to the third embodiment has a melting temperature (Tm) above 255°C, such as in the range of between 256°C and 340°C, such as between 260°C and 335°C, or between 261°C and 330°C, as determined using differential scanning calorimetry (DSC) according to ASTM D3418 (second heating, heating / cooling rate of 20°C / min).

[0198] The polymer LCP according to the third embodiment has a crystallization temperature (Tc) of less than 275°C, such as in the range of between 150°C and 275°C, such as in the range of between 155°C and 260°C, or between 160°C and 255°C, as determined using differential scanning calorimetry (DSC) according to ASTM D3418 (cooling, heating / cooling rate of 20°C / min).

[0199] The polymer LCP can be prepared by any conventional method suitable for the synthesis of liquid crystal polymers.

[0200] Polymer LCP can be prepared by thermal polycondensation of monomers and copolymers.Polymer LCP can contain chain limiters, which are monofunctional molecules that can react with hydroxyl or carboxylic acid moieties, and are used to control the molecular weight of LCP.For example, the chain limiter can be acetic acid, propionic acid and / or benzoic acid.Catalysts can also be used.Examples of catalysts are phosphorous acid, orthophosphoric acid, metaphosphoric acid, alkali metal hypophosphites such as sodium hypophosphite and phenylphosphinic acid.Stabilizers can also be used, such as phosphites.

[0201] Polymer LCP can be prepared by a solvent-free method, i.e., a method carried out in the melt in the absence of a solvent. When the condensation is solvent-free, the reaction can be carried out in an apparatus made of a material inert to the monomer. In this case, it is feasible to select an apparatus to provide enough contact of the monomer and wherein remove volatile reaction products. Suitable equipment includes stirred reactors, extruders and kneaders.

[0202] The composition suitable for producing the sheet (P) according to the invention is advantageously free of boron nitride and / or zinc oxide.

[0203] When present, the reinforcing filler is preferably selected from glass fibers, carbon fibers, and / or mineral fillers such as wollastonite, talc, calcium carbonate, silica, clay, mica, glass beads, and mixtures thereof.

[0204] Preferably, the composition comprises 1 to 75 wt.%, more preferably 5 to 60 wt.%, even more preferably 10 to 45 wt.%, and still more preferably 20 to 40 wt.% reinforcing filler based on the total weight of the composition.

[0205] According to a preferred embodiment, the reinforcing filler is glass fiber, carbon fiber or a mixture thereof, and even more preferably glass fiber.

[0206] Glass fibers are silica-based glass compounds containing several metal oxides that can be tailored to produce different types of glass. The main oxide is silicon dioxide in the form of silica sand; other oxides such as calcium, sodium, and aluminum are incorporated to lower the melting temperature and hinder crystallization.

[0207] Preferably, the glass fibers are chopped glass fibers.

[0208] All glass fiber types can be used, such as A, C, D, E, M, S, R, T glass fibers (as described in Additives for Plastics Handbook, 2nd edition, John Murphy, Chapter 5.2.3, pages 43-48), or any mixture thereof or mixtures thereof. For example, R, S and T glass fibers are high modulus glass fibers typically having an elastic modulus of at least 76, preferably at least 78, more preferably at least 80, and most preferably at least 82 GPa as measured according to ASTM D2343.

[0209] The glass fiber can have a circular cross section or a non-circular cross section, such as oval, elliptical, rectangular, cocoon-shaped. Circular glass fibers are preferred herein. In one aspect, the diameter of the circular glass fiber can be 10 μm (micrometer), or 2 μm to 15 μm, or 5 μm to 12 μm.

[0210] Glass fibers may include milled or chopped glass fibers. They may be in the form of whiskers or flakes. In other examples, they may be short glass fibers or long glass fibers. Glass fibers may have a length of about 4 millimeters or more, referred to as long fibers, and fibers shorter than this are referred to as short fibers. Short glass fibers are more preferred.

[0211] Advantageously, the LCP polymer or the composition comprises 0.5 to 5 wt.%, preferably 0.7 to 3 wt.% of PTFE, based on the total weight of the composition.

[0212] The composition may contain additional ingredients such as additional reinforcing agents, toughening agents, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, heat stabilizers, light stabilizers, flame retardants, nucleating agents, and antioxidants.

[0213] Each of the additional ingredients may be present in an amount of 0.1 to about 5 wt. %, based on the total weight of the composition.

[0214] The additional reinforcing agent may be selected, for example, from: synthetic polymer fibers, aramid fibers, aluminum fibers, titanium fibers, magnesium fibers, boron carbide fibers, rock wool fibers, steel fibers; talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate, wollastonite, barium sulfate.

[0215] The toughening agent can be selected from, for example: an elastomeric backbone comprising polyethylene and its copolymers, such as ethylene-butene; ethylene-octene; polypropylene and its copolymers; polybutene; polyisoprene; ethylene-propylene-rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS), block copolymer styrene ethylene butadiene styrene (SEBS); block copolymer styrene butadiene styrene (SBS); methacrylate-butadiene-styrene (MBS) type core-shell elastomers, or a mixture of one or more of the above.

[0216] The composition may be prepared by melt blending the polymer LCP, reinforcing filler and optionally PTFE and any other additives.

[0217] Any suitable melt blending method known in the art can be used to mix the composition of the composition. For example, the composition can be fed into a melt mixer (such as a single screw extruder or a twin screw extruder, agitator, a single screw or a twin screw kneader or a Banbury mixer), and the addition step can be to add all the components at once or to add them progressively in batches. When polymer LCP and reinforcing fillers are progressively added in batches, a part of polymer LCP and / or reinforcing fillers is first added, and then melt-mixed with the remaining polymer LCP and other optional components added subsequently, until a fully mixed composition is obtained.

[0218] The composition is then molded into a sheet (P).

[0219] Any molding technique can be used to produce the sheet (P), such as injection molding, compression molding or extrusion.

[0220] Advantageously, said sheet (P) has a thickness of about 0.1 to 1 mm, preferably 0.2 to 0.9 mm and more preferably 0.3 to 0.7 mm.

[0221] The sheet (P) according to the invention is not limited to use within a specific battery system. However, it is advantageously used in a battery system to be used in a car, such as a hybrid car or an electric car.

[0222] According to an embodiment, the present invention relates to a battery system comprising:

[0223] - a battery block comprising at least two adjacently stacked battery cells;

[0224] - a fastening member for holding the at least two adjacent battery cells, comprising: (i) a pair of end plates, each end plate being disposed at one end of the at least two battery cells, and (ii) a metal band disposed at a side wall of the battery block extending in a stacking direction of the battery cells and connected to the end plates at both ends;

[0225] Wherein each of said end plates is applied to at least one sheet (P) as defined above.

[0226] Figure 1 An exemplary battery system including the sheet (P) according to this embodiment of the invention is shown, wherein the shapes, sizes and thicknesses of different parts are not proportional to each other.

[0227] refer to Figure 1 The battery system includes a battery block 1 having a plurality of adjacently stacked battery cells 2 , and a fastening member 3 that holds the battery cells 2 of the battery block 1 .

[0228] Preferably, the battery cell 2 is a lithium-ion battery, however, other types of batteries may also be used depending on the circumstances.

[0229] exist Figure 1 In the embodiment, the battery cell 2 is shown as a rectangular battery. However, batteries having other shapes and arranged in different configurations may be provided.

[0230] The battery cells 2 are held in a fixed position by a fastening member 3 including a pair of end plates 4 provided at the ends of adjacently stacked battery cells 2 and a metal band 5 connected to the end plates 4 to hold the battery stack in a compressed state.

[0231] Optionally, a pair of side panels ( Figure 1 The end plate (not shown) can be arranged at the side wall of the battery block 1, extending along the stacking direction of the battery cells 2, and connected to the end plate 4 or the metal strip 5.

[0232] like Figure 1 As shown, the end plate 4 has a rectangular shape that is the same shape as the battery cell 2. It is preferred that the end plate 4 has the same shape and size as the battery cell 2 (or slightly larger) so that the end plate 4 connected by the metal band 5 is not deformed, and thus expansion at the center area of ​​the battery cell 2 can be prevented.

[0233] However, the end plates 4 may be provided in any shape and size, depending on the shape and size of the battery cells 2 and the intended end use of the battery system 1 .

[0234] Preferably, the end plate 4 is made of metal, such as aluminum or an aluminum alloy, or of a plastic resin, more preferably a thermoplastic resin.

[0235] like Figure 1As shown, the sheet (P) 6 according to the invention has the same shape and dimensions as the end plate 4 .

[0236] However, the sheet (P) 6 may be provided in any shape and size, depending on the final shape and size of each end plate 4 , the battery cell 2 , and the battery system 1 .

[0237] Preferably, the sheet 6 is applied to the end panel 4 via an adhesive layer, such as a pressure sensitive adhesive, or alternatively the sheet 6 may be laminated to the end panel 4 .

[0238] According to another embodiment, at least one sheet (P) 6 may be inserted between at least one pair, more preferably between each pair of adjacent stacked battery cells 2 ( Figure 1 not shown).

[0239] Preferably, the sheet 6 is inserted between at least one pair of adjacent stacked battery cells 2 and held in place by the mechanical action of the metal strip 5. Alternatively, the sheet 6 is held in place by an adhesive layer, such as a pressure sensitive adhesive.

[0240] According to this embodiment, the present invention relates to a battery system comprising:

[0241] - a battery block comprising at least two adjacently stacked battery cells;

[0242] - a fastening member for holding the at least two battery cells, comprising: (i) a pair of end plates, each end plate being disposed at one end of the at least two adjacently stacked battery cells, and (ii) a metal band disposed at a side wall of the battery block extending in a stacking direction of the battery cells and connected to the end plates at both ends;

[0243] Therein, at least one sheet (P) as defined above is inserted between at least two, more preferably all, adjacently stacked battery cells (2).

[0244] According to this embodiment, the use of a sheet (P) instead of the conventional spacer called aerogel used to date allows to obtain advantages in terms of enhanced high temperature resistance (even above 400°C), extended lifetime and stable performance under harsh environmental conditions (for example, at extremely low or high temperatures and under severe compression).

[0245] According to another and preferred embodiment, the present invention relates to a battery system (1) comprising:

[0246] - a battery block comprising at least two adjacently stacked battery cells;

[0247] - a fastening member for holding the at least two battery cells, comprising: (i) a pair of end plates, each end plate being disposed at one end of the at least two adjacently stacked battery cells, and (ii) a metal band disposed at a side wall of the battery block extending in a stacking direction of the battery cells and connected to the end plates at both ends;

[0248] wherein at least one sheet (P) as defined above

[0249] - applied to each of said end plates; and

[0250] - inserted between at least two adjacent stacked battery cells.

[0251] According to this embodiment, the use of the sheet (P) joined with the end plates and interposed between each pair of adjacent stacked battery cells allows for excellent electrical insulation of the entire battery system.

[0252] Should the disclosure of any patents, patent applications, and publications incorporated by reference into this application conflict with the description of this application to the extent that a term may be unclear, this description shall take precedence.

[0253] The present invention will be further described with reference to the following examples.

[0254] Experimental Section

[0255] Material

[0256] LCP SRT 300 (terephthalic acid / biphenol / 4-hydroxybenzoic acid 25 / 25 / 50 molar ratio) was obtained from Solvay Specialty Polymers USA, LLC.

[0257] Round chopped E-glass fibers, polycarbonate (PC), and epoxy resins are commercially available.

[0258] Sheet manufacturing

[0259] 100 sheets having a size of 150 mm*100 mm and a thickness of 0.5 mm were prepared by blending LCP polymer with 30 wt. % of glass fiber and injection molding the blend at a temperature of 350 to 430° C. and a pressure of 80 to 120 MPa using a high speed injection molding machine.

[0260] The sheets were tested as follows.

[0261] For comparison, sheets of the same size and thickness were obtained from a composition comprising - polycarbonate (PC) without glass fibers

[0262] - Commercial epoxy resin containing 30 wt.% glass fibers.

[0263] Test 1-Aging and electrical characteristics evaluation

[0264] 32 sheets were placed in an oven at 400°C and kept at the same temperature for 30 minutes.

[0265] Afterwards, the sheets were tested for the following properties:

[0266] (A1) 1000V DC (direct current) for 15 seconds: Insulation resistance must be > 1GΩ (gigaohm)

[0267] (B1) 3000V DC for 15 seconds: Withstand voltage leakage current must be <0.1mA

[0268] (C1) Thermal conductivity must be <0.05W / (m·K)

[0269] The sheet according to the invention maintained good shape after 30 minutes and passed all tests (A1 ), (B1 ) and (C1 ).

[0270] The sheets made of polycarbonate were already decarbonized after 30 minutes.

[0271] The sheet made of epoxy resin disintegrated after 30 minutes and became separate fiberglass cloths.

[0272] Test 2 - Low temperature fatigue test

[0273] The purpose of this test is to confirm whether the sheet is broken or meets the insulation withstand voltage requirements.

[0274] The test was performed as follows.

[0275] 1. The temperature of the environmental box was brought to a temperature of -30°C by decreasing the temperature at a rate of 5°C / min. Once -30°C was reached, the temperature was kept stable and 5 sheets according to the invention (each on an aluminum plate) were placed in the environmental box. The sheets were stored for 1 hour.

[0276] 2. Take the sheets out of the environmental chamber and apply a pressure of 20 KN to the sheets for 30 minutes. Then bend the sheets 10° at a rate of 1° / s, then release, and do it back and forth 50 times.

[0277] After this treatment, the sheets were evaluated as follows:

[0278] (A2) Insulation resistance under load pressure test ≥ 1000MΩ@1000V DC, for 60 seconds;

[0279] (B2) Withstand voltage leakage current ≤1mA@3000V DC, for 60 seconds.

[0280] Tests (A2) and (B2) were repeated every 50 times until 2000 bends were reached.

[0281] After completion of the fatigue test (2000 bends), the appearance of the sample had not changed significantly, and the sheet according to the invention passed both tests (A2) and (B2).

Claims

1. A sheet [sheet (P)] having a thickness equal to or less than 3 mm and made of at least one liquid crystal polymer [polymer LCP].

2. The sheet (P) according to claim 1, which is made of a composition comprising: - at least one liquid crystal polymer [polymer LCP]; - from about 5 wt. % to about 50 wt. % of at least one reinforcing filler.

3. The sheet (P) according to claim 2, said composition comprising 50 to 90 wt.% of said polymer LCP, based on the total weight of the composition.

4. Sheet (P) according to claim 2, said composition comprising from 1 to 75 wt. %, based on the total weight of the composition, of at least one reinforcing filler.

5. The sheet material (P) according to any one of the preceding claims, wherein The polymer LCP is obtained by the polycondensation reaction of (I) terephthalic acid, (II) at least one aromatic diol, and (III) at least one aromatic dicarboxylic acid and / or hydroxycarboxylic acid.

6. The sheet (P) according to claim 5, wherein Said - at least one aromatic diol is represented by a formula selected from the group consisting of: HO-Ar1-OH(1) HO-Ar2-T1-Ar3-OH(2) in Ar1 to Ar3 are each independently selected from C6-C 30 Aryl, which may be optionally substituted by one or more substituents selected from the group consisting of halogen, C1-C 15 Alkyl, and C6-C 15 aryl; and T1 is selected from the group consisting of: a bond, O, S, -SO2-, -C(=O)-, and C1-C 15 alkyl; and / or - at least one aromatic dicarboxylic acid is represented by a formula selected from the group consisting of: HOOC-Ar1-COOH(3) HOOC-Ar2-T2-Ar3-COOH(4) in Ar1 to Ar3 are independently selected and have the meanings as defined above; and T2 is selected from the group consisting of: a σ bond, O and S; and / or - the at least one aromatic hydroxycarboxylic acid is represented by a formula selected from the group consisting of HO-Ar1-COOH(5) HO-Ar2-Ar3-COOH(6) in Ar1 to Ar3 are independently selected and have the meanings defined above.

7. The sheet (P) according to any one of claims 1 to 4, wherein The polymer LCP comprises: - 40 to 98 mol.% of repeating units of formula (I): - 1 to 20 mol.% of repeating units of formula (IIa), (IIb), (IIc) and / or (IId): as well as - 1 to 12 mol.% of repeating units of formula (IIIa) and / or (IIIb): Based on total moles of polymer in LCP.

8. The sheet (P) according to any one of claims 1 to 4, wherein The polymer LCP comprises: a) 40 to 98 mol.% of repeating units of formula (i): b) 1 to 30 mol.% of repeating units of formula (ii): as well as c) a repeating unit having two carboxyl groups of formula (iii): - 1 to 23 mol.% of repeating units of formula (iiia): and / or - 1 to 13 mol.% of repeating units of formula (iiib):

9. The sheet (P) according to any one of claims 2 to 8, wherein The at least one reinforcing filler is selected from glass fibers, carbon fibers, glass beads, and / or mineral fillers, and mixtures thereof.

10. The sheet material (P) according to any one of the preceding claims, wherein The polymer LCP or the composition further comprises 0.5 to 5 wt. % of poly(tetrafluoroethylene) (PTFE), based on the total weight of the polymer LCP or the composition.

11. A battery system (1), comprising: - a battery block comprising at least two adjacently stacked battery cells (2); - a fastening member (3) for holding the at least two battery cells, comprising: (i) a pair of end plates (4), each end plate being provided at one end of the at least two battery cells, and (ii) a metal band (5) provided at a side wall of the battery block extending in a stacking direction of the battery cells and connected to the end plates (4) at both ends; wherein at least one sheet (P)(6) according to any one of claims 1 to 10: - applied to each of said end plates (4); and / or - inserted between at least two adjacently stacked battery cells (2).

12. The battery system 1 according to claim 11, wherein: At least one sheet material (P) according to any one of claims 1 to 10 is applied to each of the end panels (4).

13. The battery system 1 according to claim 12, wherein: The sheet (P) (6) is applied to the end panel (4) via an adhesive layer, such as a pressure sensitive adhesive.

14. The battery system 1 according to claim 13, wherein: The sheet material (P) (6) is laminated to the end plate (4).

15. The battery system 1 according to claim 11, wherein: At least one sheet (P) (6) according to any one of claims 1 to 10 is inserted between at least two adjacent stacked battery cells (2).

16. The battery system 1 according to claim 11 or 15, wherein: At least one sheet (P) (6) according to any one of claims 1 to 10 is inserted between each pair of adjacent stacked battery cells (2).

17. The battery system 1 according to claim 11, wherein: At least one sheet (P) (6) according to any one of claims 1 to 10 - applied to each of said end plates (4) and - inserted between at least two, preferably all pairs of adjacently stacked battery cells (2).

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