Gap filler composition and battery pack

Abstract

A gap filler composition according to embodiments of the present invention comprises a siloxane-based resin, a filler containing thermally conductive inorganic particles and graphite particles, a catalyst, and an amino-silicone-based dispersant. The content of the thermally conductive inorganic particles is 65-95 wt % relative to the total weight of the composition. The content of the graphite particles is 1-20 wt% relative to the total weight of the composition. Provided is a gap filler composition that, by utilizing the amino-silicon-based dispersant and the graphite particles, maintains low specific gravity and possesses enhanced thermal conductivity and viscosity stability A battery pack utilizing the gap filler composition is provided.

Description

Gap filler composition and battery pack

[0001] The present invention relates to a gap filler composition and a battery pack. More particularly, the present invention relates to a gap filler composition comprising a siloxane-based resin and a battery pack comprising a gap filler formed using the same.

[0002]

[0003] Secondary batteries, which can be repeatedly charged and discharged, are widely used as power sources for portable electronic devices such as cell phones and laptops. For example, lithium secondary batteries boast high operating voltage, energy density, and rate characteristics, and are recently being utilized as power sources for electric vehicles.

[0004] For example, a battery cell is defined by a lithium secondary battery, and a plurality of battery cells are assembled to form a battery module. The battery modules can be assembled to form a high-capacity / high-output battery pack applicable to electric vehicles.

[0005] To apply the battery pack to a vehicle such as an electric vehicle, the battery pack can be secured to a battery support plate and a gap filler composition can be used to secure the battery pack.

[0006] The above gap filler composition application process can be incorporated into the overall electric vehicle production platform. Therefore, to maintain automotive process efficiency and reliability, a gap filler composition that cures within a predetermined time and provides desired properties may be required.

[0007] There is a need to design a composition that can form a gap filler having improved thermal conductivity for dissipating heat generated by repeated charging / discharging of the battery pack, and having appropriate absorbency / elasticity against external impact while having low weight / specific gravity.

[0008] For example, Korean Patent Publication No. 10-2402503 discloses a battery pack structure including a battery module and a gap filler. However, it does not disclose the specific properties and composition of the gap filler.

[0009]

[0010] An object of the present invention is to provide a gap filler composition that provides improved thermal properties, mechanical properties, and storage stability.

[0011] One object of the present invention is to provide a battery pack including a gap filler formed of the gap filler composition.

[0012]

[0013] 1. A gap filler composition comprising: a siloxane-based resin; a filler including thermally conductive inorganic particles and graphite particles; a catalyst; and an amino-silicon-based dispersant, wherein the content of the thermally conductive inorganic particles is 65 wt% to 95 wt% of the total weight of the composition, and the content of the graphite particles is 1 wt% to 20 wt% of the total weight of the composition.

[0014] 2. A gap filler composition in the above 1, wherein the content of the thermally conductive inorganic particles is 71% by weight to 89% by weight of the total weight of the composition.

[0015] 3. A gap filler composition in the above 1, wherein the content of the graphite particles is 4 wt% to 16 wt% of the total weight of the composition.

[0016] 4. A gap filler composition in the above 1, wherein the content of the filler is more than 80% by weight and less than or equal to 95% by weight of the total weight of the composition.

[0017] 5. A gap filler composition in the above 1, wherein the content of the amino-silicone dispersant is 0.1 wt% to 3 wt% of the total weight of the composition.

[0018] 6. A gap filler composition in the above 1, wherein the thermally conductive inorganic particles include aluminum hydroxide particles.

[0019] 7. A gap filler composition in the above 6, wherein the aluminum hydroxide particles are particles that are not surface-treated with an alkyl group or an alkylsilane group.

[0020] 8. A gap filler composition in the above 1, wherein the graphite particles include at least one selected from the group consisting of impression graphite, expanded graphite, and spheroidal graphite.

[0021] 9. In the above 8, the gap filler composition wherein the spherical graphite has an average particle diameter of 1 ㎛ to 50 ㎛.

[0022] 10. A gap filler composition in the above 1, wherein the siloxane-based resin comprises a first siloxane-based resin including an unsaturated terminal group and a second siloxane-based resin including a saturated terminal group.

[0023] 11. A gap filler composition according to the above 10, wherein the siloxane-based resin further comprises a crosslinking agent including a siloxane-based resin having methyl groups bonded to silicon atoms at both terminals.

[0024] 12. A gap filler composition having a specific gravity of 3 or less in the above 1.

[0025] 13. A gap filler composition having a viscosity of 850 Paㆍs or less at 25℃ in the above 1.

[0026] 14. A battery pack comprising a plurality of battery modules; a support plate; and a gap filler formed between the battery modules and the support plate using a gap filler composition according to the embodiments described above.

[0027]

[0028] Gap filler compositions according to exemplary embodiments of the present invention may include thermally conductive inorganic particles as a filler. The thermally conductive inorganic particles may include aluminum hydroxide particles. In some embodiments, the thermally conductive inorganic particles may satisfy a predetermined content range based on the total weight of the composition. In some embodiments, untreated aluminum hydroxide particles may be used.

[0029] According to exemplary embodiments, the gap filler composition may include graphite particles as a filler. In some embodiments, the graphite particles may satisfy a predetermined content range based on the total weight of the composition.

[0030] The specific gravity of the gap filler composition can be reduced by the thermally conductive inorganic particles, and thermal conductivity can be improved while maintaining the reduced specific gravity by the graphite particles. Accordingly, the gap filler composition can be applied to a vehicle battery pack to realize a weight reduction of the battery pack, and can quickly transfer heat generated during the charge / discharge process to the outside.

[0031] The above thermally conductive inorganic particles and the graphite particles satisfy a predetermined content range based on the total weight of the composition, so that the storage stability of the gap filler composition can be secured.

[0032] According to exemplary embodiments, the gap filler composition may include an amino-silicone-based dispersant. The amino-silicone-based dispersant may increase dispersibility between the filler and the siloxane-based resin, thereby enhancing the storage stability of the composition.

[0033]

[0034] FIG. 1 is a schematic cross-sectional view illustrating a battery pack according to exemplary embodiments.

[0035]

[0036] According to embodiments of the present invention, a gap filler composition comprising a siloxane-based resin, a filler, a catalyst, and a dispersant, and having improved thermal and mechanical properties is provided. Furthermore, according to embodiments of the present invention, a battery pack using the gap filler composition is provided.

[0037] Gap filler composition

[0038] A gap filler composition according to exemplary embodiments may include a siloxane-based resin, a filler, a catalyst, and a dispersant.

[0039] The above siloxane-based resin may be provided as a base component that provides curability to the gap filler composition. According to exemplary embodiments, the siloxane-based resin may include a first siloxane-based resin and a second siloxane-based resin.

[0040] The first siloxane-based resin may be a siloxane-based resin containing crosslinkable terminal groups. According to exemplary embodiments, the first siloxane-based resin may be a siloxane-based resin containing unsaturated terminal groups (e.g., vinyl groups) at both ends of the molecule.

[0041] For example, the first siloxane resin may include a compound represented by the following chemical formula 1.

[0042] [Chemical Formula 1]

[0043]

[0044] In some embodiments, 25 of the first siloxane resin o At C, the viscosity can be from 50 cps to 150,000 cps, from 70 cps to 1,500 cps, from 100 cps to 1,500 cps, from 200 cps to 1,500 cps, or from 300 cps to 1,200 cps.

[0045] In some embodiments, the weight average molecular weight of the first siloxane-based resin may be adjusted in consideration of the viscosity within the above-described range. For example, the weight average molecular weight of the first siloxane-based resin may be 1,500 to 50,000, 10,000 to 50,000, 10,000 to 30,000, or 10,000 to 25,000.

[0046] Within the above molecular weight and viscosity ranges, the curing characteristics and curing speed described below can be more easily achieved, and appropriate application characteristics and flowability of the gap filler composition can be secured. If the above molecular weight and viscosity ranges are exceeded, the viscosity change rate over time of the gap filler composition may increase, resulting in reduced storage stability.

[0047] In chemical formula 1, n can be adjusted in consideration of the viscosity range. For example, n can be a natural number in the range of 40 to 800, 80 to 800, 100 to 800, 130 to 700, or 150 to 700.

[0048] The content of the first siloxane-based resin among the total weight of the gap filler composition (e.g., solid content) may be 1.5 wt% to 20 wt%. In one embodiment, the content of the first siloxane-based resin may be 5 wt% to 13 wt%, 7 wt% to 12 wt%, or 7.5 wt% to 10 wt%. Within the above content range, a gap filler having appropriate hardness and elasticity can be effectively formed.

[0049] The above second siloxane-based resin may be a siloxane-based resin having a different structure from the above first siloxane-based resin.

[0050] The above second siloxane resin is included as a chain extender or chain regulator of the gap filler composition, and can control the overall viscosity, flowability, crosslinking property, etc. of the composition.

[0051] According to exemplary embodiments, the second siloxane-based resin may be a siloxane-based resin in which a saturating group (e.g., a hydrogen atom) is bonded to silicon atoms at both terminals.

[0052] The above second siloxane resin is included as a chain extender or chain regulator in the gap filler composition, and can control the overall viscosity, flowability, crosslinking property, etc. of the composition.

[0053] For example, the second siloxane resin may include a compound represented by the following chemical formula 2.

[0054] [Chemical Formula 2]

[0055]

[0056] In some embodiments, 25 of the second siloxane resin o At C, the viscosity can be from 10 cps to 1,500 cps, from 100 cps to 1,500 cps, from 200 cps to 1,500 cps, or from 300 cps to 1,200 cps.

[0057] The weight average molecular weight of the second siloxane-based resin can be adjusted depending on the viscosity range. For example, the weight average molecular weight of the second siloxane-based resin can be 500 to 50,000, 10,000 to 50,000, 10,000 to 30,000, or 10,000 to 25,000.

[0058] Within the above molecular weight and viscosity ranges, the curing characteristics and curing speed described below can be more easily achieved, and appropriate application characteristics and flowability of the gap filler composition can be secured. If the above molecular weight and viscosity ranges are exceeded, the viscosity change rate over time of the gap filler composition may increase, resulting in reduced storage stability.

[0059] In chemical formula 2, m can be adjusted in consideration of the molecular weight and viscosity ranges. For example, m can be a natural number in the range of 10 to 700, 20 to 700, 30 to 700, 50 to 700, 100 to 700, or 130 to 700.

[0060] The content of the second siloxane-based resin among the total weight of the gap filler composition (e.g., solid content) may be 0.5 wt% to 10 wt%. In one embodiment, the content of the second siloxane-based resin may be 2 wt% to 10 wt%, 2 wt% to 7 wt%, or 2 wt% to 5 wt%. Within the above content range, a gap filler having appropriate hardness and elasticity can be effectively formed.

[0061] According to exemplary embodiments, the content of the siloxane-based resin in the total weight (e.g., solid content) of the gap filler composition may be 10 wt% or more. According to exemplary embodiments, the content of the siloxane-based resin may be 10 wt% to 23 wt%. In one embodiment, the content of the siloxane-based resin may be 10 wt% to 20 wt%, 10 wt% to 18 wt%, 10 wt% to 15 wt%, or 10 wt% to 14 wt%.

[0062] In some embodiments, the gap filler composition may further include a crosslinking agent. The crosslinking agent may be a siloxane-based resin having relatively low viscosity and having methyl groups bonded to silicon atoms at both ends. For example, the crosslinking agent may include a compound represented by Chemical Formula 3.

[0063] [Chemical Formula 3]

[0064]

[0065] In one embodiment, the viscosity of the crosslinking agent may be less than the viscosity of the second siloxane-based resin. In one embodiment, the viscosity of the crosslinking agent may be 25 oIn C, the viscosity can be less than 100 cps, and n in chemical formula 3 can be adjusted considering the above viscosity range.

[0066] A crosslinking agent may be included in the crosslinking composition described below. The content of the crosslinking agent in the total weight of the gap filler composition may be 0.1 wt% to 0.5 wt%.

[0067] The above catalyst can be used as a regulator for promoting crosslinking and / or interaction of the first siloxane-based resin and / or the second siloxane-based resin of the gap filler composition to obtain the curing characteristics and curing speed described below.

[0068] In some embodiments, the catalyst may comprise a compound or complex of Pt(II), Pt(IV), and / or Pt(0). For example, the catalyst may comprise chloroplatinic acid, Ashby's catalyst, or Karstedt catalyst.

[0069] According to exemplary embodiments, the catalyst may include an organic-inorganic hybrid catalyst containing platinum and silicon. In one embodiment, the platinum may be Pt(0) having an oxidation state of 0.

[0070] The catalyst may contain Pt atoms and Si2O groups (-Si-O-Si-) within the molecule. For example, silicon (Si) atoms of the Si2O group may be bonded to vinyl groups, and Pt atoms may be coordinated or captured by the vinyl groups.

[0071] According to exemplary embodiments, the weight ratio of platinum (Pt) to the weight of silicon (Si) atoms and oxygen atoms (O) in the catalyst may be 1.2 to 2.0, 1.2 to 1.5, or 1.25 to 1.45.

[0072] By using a catalyst within the above weight ratio range, appropriate catalyst activity can be maintained through Pt atoms. Accordingly, the curing characteristics and curing speed of the gap filler composition described below can be easily achieved using the catalyst.

[0073] For example, the catalyst may include a unit represented by the following chemical formula 4 within the molecule.

[0074] [Chemical Formula 4]

[0075] Ptㆍ[(CH2=CH(CH3)2Si)O]

[0076] In some embodiments, the content of the catalyst may be 0.01 wt% to 0.05 wt% of the total weight of the composition. Within this range, an appropriate curing speed can be achieved while preventing excessive hardness / elasticity increase of the gap filler.

[0077] The above filler may be included as a component that increases the thermal conductivity of the gap filler and thus improves the heat dissipation characteristics of the battery pack.

[0078] The above filler may include thermally conductive inorganic particles. Examples of the thermally conductive inorganic particles include aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), hydromagnesite (Mg5(CO3)4(OH)2·4H2O), magnesia, alumina, aluminum nitride (AlN), boron nitride (BN), silicon nitride, SiC, ZnO, BeO, etc.

[0079] According to exemplary embodiments, the filler may include aluminum hydroxide (Al(OH)3) particles. The aluminum hydroxide particles have a relatively low specific gravity compared to alumina particles, and can lower the overall specific gravity of the gap filler composition and improve filling properties and flowability.

[0080] In some embodiments, the gap filler composition may not include alumina particles. In one embodiment, the thermally conductive inorganic particles may consist essentially of aluminum hydroxide particles.

[0081] In some embodiments, the thermally conductive inorganic particles or aluminum hydroxide particles may be non-surface-treated particles. For example, the thermally conductive inorganic particles or aluminum hydroxide particles may be bare particles that have not been surface-treated with an alkyl group or an alkylsilane group. Therefore, the specific gravity reduction effect resulting from the use of the aluminum hydroxide particles can be more effectively implemented. For example, the thermally conductive inorganic particles may not be surface-treated with an alkylsilane agent such as hexyltrimethoxysilane.

[0082] The above thermally conductive inorganic particles can be included in the largest amount (weight %) in the gap filler composition. Therefore, the thermal conductivity properties of the gap filler composition can be sufficiently increased.

[0083] In some embodiments, the content of the thermally conductive inorganic particles in the total weight of the composition may be from 65 wt% to 95 wt%, from 70 wt% to 89 wt%, from 71 wt% to 87 wt%, or from 71 wt% to 83 wt%.

[0084] The above filler may include graphite particles. The inclusion of the graphite particles may improve thermal conductivity while maintaining a reduced specific gravity of the gap filler composition.

[0085] Examples of the above graphite particles include natural graphite, artificial graphite, activated carbon, carbon black, fullerene, carbon nanotubes, and graphene oxide.

[0086] According to exemplary embodiments, natural graphite may be used as the graphite particles. The natural graphite may include spheroidal graphite, expanded graphite, and / or spheroidal graphite.

[0087] In some embodiments, spherical graphite may be used as the graphite particles. The average particle size of the spherical graphite may be from 0.1 μm to 50 μm, or from 1 μm to 30 μm.

[0088] By including spherical graphite as graphite particles, the thermal conductivity of the gap filler composition can be increased while improving the viscosity change rate, and thus the storage stability of the gap filler composition can be improved.

[0089] In some embodiments, expanded graphite may be used as the graphite particles.

[0090] In some embodiments, the graphite particles may include both spheroidal graphite and expanded graphite.

[0091] In one embodiment, the weight ratio of the spherical graphite and the expanded graphite may be 1:0.1 to 10. The spherical graphite and the expanded graphite may be included in the above range and a dispersant described below may be included to reduce the viscosity change rate of the gap filler composition.

[0092] The content of the graphite particles in the total weight of the composition may be 1 wt% to 20 wt%.

[0093] In some embodiments, the content of the graphite particles in the total weight of the composition may be from 1 wt% to 20 wt%, from 2 wt% to 18 wt%, or from 4 wt% to 16 wt%.

[0094] Within the above range, the thermal and viscosity properties can be improved simultaneously while maintaining the reduced specific gravity of the gap filler composition. For example, if the content of graphite particles is below the above range, the thermal conductivity of the gap filler composition may not be improved, and if the content of graphite particles exceeds the above range, the viscosity change rate of the gap filler composition may increase, making it difficult to ensure storage stability.

[0095] In some embodiments, the filler may be substantially free of silica particles or organic particles. Here, substantially free of silica particles may refer to a case where the content is 0.1 wt% or less based on the total weight of the composition. The organic particles may include, for example, hollow organic particles such as acrylic particles such as poly(methylmethacrylate) (PMMA), epoxy particles, nylon particles, styrene particles, styrene / vinyl copolymer particles, etc.

[0096] Since silica particles or organic particles are substantially not included, improved thermal conductivity properties can be maintained.

[0097] According to exemplary embodiments, the content of the filler including the thermally conductive inorganic particles and graphite particles can be maintained at 95 wt% or less of the total weight of the composition.

[0098] For example, the content of the thermally conductive inorganic particles in the total weight of the composition is 70 wt% to 90 wt%, and the content of the graphite particles is 1 wt% to 20 wt%, but the total content of the thermally conductive inorganic particles and the graphite particles can be adjusted so that each content corresponds to 95 wt% or less.

[0099] Within the above content range, viscosity measurement and viscosity change control of the gap filler composition are possible, thereby ensuring storage stability.

[0100] In some embodiments, the filler may be from 75 wt% to 95 wt%, from more than 80 wt% to 95 wt%, from 81 wt% to 90 wt%, from 82 wt% to 88 wt%, or from 82 wt% to 87 wt% of the total weight of the composition.

[0101] Storage stability of a gap filler composition having low specific gravity and high thermal conductivity within the above content range can be secured together.

[0102] The gap filler composition according to exemplary embodiments may further comprise an amino-silicone based dispersant.

[0103] In some embodiments, the amino-silicone dispersant may comprise an amino silicone oil comprising siloxane units and amino groups.

[0104] For example, the amino-silicone dispersant may include a siloxane unit represented by the following general formula 1 and an amino-containing group represented by the following general formula 2. The amino-containing group may be bonded to a silicon atom.

[0105] [General Formula 1]

[0106]

[0107] In general formula 1, R a and R b Each can be hydrogen, a C1-C5 alkyl group, or any one of the groups represented by the general formula 2.

[0108] [General Formula 2]

[0109] -ALK1-NH-ALK2-NH-R c

[0110] General formula 1, R c may be hydrogen or a C1-C5 alkyl group. ALK1 and ALK2 may each independently be a C1-C6 alkylene group.

[0111] For example, a siloxane unit represented by the general formula 1 may be included as a repeating unit of the amino-silicone dispersant. R of at least one siloxane unit among the siloxane units in which an amino-containing group represented by the general formula 2 is repeated a or R b can be combined as

[0112] In one embodiment, the amino-silicone-based dispersant may include a terminal amine group (-NH2). The inclusion of an amine group at the terminal of the amino-silicone-based dispersant may enhance the dispersibility of aluminum hydroxide.

[0113] By including the amino-silicone dispersant, sufficient dispersibility can be secured even when non-surface-treated thermally conductive inorganic particles are used. Therefore, uniform thermal conductivity can be achieved throughout the gap filler while reducing the composition's specific gravity.

[0114] Additionally, a dispersant containing a siloxane unit can be used to stabilize the filler at the interface between the siloxane-based resin and the filler described above. Accordingly, agglomeration of the filler can be prevented, the viscosity of the composition can be stably maintained, and flowability can be improved.

[0115] In some embodiments, a dispersant containing a hydroxyl group or an epoxy group may not be used as the dispersant. Accordingly, side reactions with the filler and siloxane-based resin due to the hydroxyl group or epoxy group can be prevented, and the composition dispersibility and thermal conductivity uniformity can be improved.

[0116] In some embodiments, the content of the amino-silicone-based dispersant may be 0.1 wt% to 3 wt% of the total weight of the composition. In one embodiment, the content of the amino-silicone-based dispersant may be 0.1 wt% to 0.5 wt%, or 0.2 wt% to 0.4 wt%. Within the above range, the dispersibility of the aluminum hydroxide particles can be improved and an increase in the specific gravity of the composition can be prevented.

[0117] In some embodiments, the amine value, defined as the amount of 0.1 N HCl titrant required to neutralize 10 g of the amino-silicone-based dispersant, may be 1 mgKOH / g to 80 mgKOH / g, 10 mgKOH / g to 60 mgKOH / g, or 20 mgKOH / g to 50 mgKOH / g. Within this range, the filler stabilization effect described above can be effectively implemented.

[0118] In some embodiments, the gap filler composition may further include additives to enhance the conductivity and curability of the composition within a range that does not inhibit the actions of the siloxane-based resin, the catalyst, and the filler described above. For example, the additives may include flame retardants, surfactants, silane coupling agents, colorants (e.g., pigments), antioxidants, plasticizers, and the like. The additives may be included in the composition as a remainder or extra amount, excluding the siloxane-based resin, catalyst, and filler described above.

[0119] For example, examples of the flame retardant include organic flame retardants such as melamine cyanurate, and inorganic flame retardants such as magnesium hydroxide. In one embodiment, a liquid type flame retardant material (such as triethyl phosphate (TEP) or tris(1,3-chloro-2-propyl)phosphate (TCPP)) may be used.

[0120] For example, examples of the surfactant include polyethylene glycol, polypropylene glycol, oleic acid ethoxylate, alkylphenol ethoxylate, copolymers of ethylene oxide and propylene oxide, and silicone polymers.

[0121] Examples of the above silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercaptopropyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, γ-acetoacetatepropyltrimethoxysilane, etc.

[0122] As the above antioxidants, phenol compounds, quinone compounds, amine compounds, phosphorus compounds, phosphite compounds, thioether compounds, etc. can be used.

[0123] Examples of the above plasticizers include tetraethylene glycol monobutyl ether (3,6,9,12-tetraoxahexadecanol), triethylene glycol monobutyl ether (3,6,9-trioxatridecanol), diethylene glycol monobutyl ether (2-(2-butoxyethoxy)ethanol), propylene glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether (1-methoxy-2-propanol), propylene glycol monomethyl ether acetate, polyethylene glycol, and glycerin.

[0124] In exemplary embodiments, the specific gravity of the gap filler composition may be 3 or less, or 2.75 or less. In some embodiments, the specific gravity of the gap filler composition may be 1.8 to 2.7, or 2.0 to 2.5.

[0125] The above specific gravity is 4 under 1 atm. o C is a numerical value measured as a relative ratio of the density of water to a standard.

[0126] A gap filler having improved mechanical stability and desired heat dissipation characteristics can be obtained without increasing the weight of the battery pack within the above specific gravity range.

[0127] In exemplary embodiments, the viscosity of the gap filler composition may be 1,000 Pa·s or less, 900 Pa·s or less, or 200 Pa·s or more and 850 Pa·s or less. The viscosity may be 25 o It may be a value measured in C.

[0128] The above viscosity may refer to the viscosity on the same day (within 24 hours) that the gap filler composition was manufactured.

[0129] The stability of the gap filler composition is secured within the above viscosity range, enabling long-term storage.

[0130] The gap filler composition may be prepared as a two-component composition. For example, the gap filler composition may be prepared by separately preparing a main composition and a crosslinking composition, and then mixing the main composition and the crosslinking composition.

[0131] According to embodiments of the present invention, the above-described first siloxane resin may be commonly included in the subject composition and the crosslinking composition.

[0132] According to exemplary embodiments, the gap filler composition may be prepared as a two-component composition. For example, the gap filler composition may be prepared by separately preparing a main composition and a crosslinking composition, and then mixing the main composition and the crosslinking composition.

[0133] The above-mentioned subject composition may include the first siloxane-based resin, the thermally conductive inorganic particles, and the catalyst. The above-mentioned crosslinking composition may include the first siloxane-based resin, the second siloxane-based resin, and the filler.

[0134] For example, a crosslinking composition including the second siloxane-based resin may be mixed with the catalyst and the first siloxane-based resin in a state in which they are distributed in the subject composition. Accordingly, since the second siloxane-based resin is introduced in a state in which crosslinking points are distributed in the subject composition, curing efficiency can be enhanced.

[0135] In some embodiments, the first siloxane-based resin may also be included in the crosslinking composition. The weight of the first siloxane-based resin included in the subject composition may be greater than the weight of the first siloxane-based resin included in the crosslinking composition.

[0136] The thermally conductive inorganic particles may be divided and included in the main composition and the crosslinking composition. In one embodiment, the ratio of the amount of the filler included in the main composition to the amount of the filler included in the crosslinking composition may be 1.0 to 1.5, or 1.0 to 1.35. Within the above ratio range, the thermal conduction efficiency can be enhanced through the uniform distribution of the thermally conductive inorganic particles.

[0137] The graphite particles may be included in the crosslinking composition. The graphite particles may be included in the subject composition and the crosslinking composition separately.

[0138] For example, a crosslinking composition comprising a second siloxane-based resin and graphite particles can be mixed with a subject composition that does not comprise a second siloxane-based resin and graphite particles. Accordingly, since the graphite particles can be introduced with enhanced curing efficiency, the thermal conductivity of the composition can be uniformly improved.

[0139] As described above, an amino-silicone-based dispersant may be used to improve the dispersibility of untreated particles. The amino-silicone-based dispersant may also be separately included in the subject composition and the crosslinking composition.

[0140] Battery Pack

[0141] FIG. 1 is a schematic cross-sectional view illustrating a battery pack according to exemplary embodiments.

[0142] Referring to FIG. 1, a battery pack (100) includes a battery module (110) and a support plate (130), and may include a gap filler (120) formed on the battery module (110) and the support plate (130).

[0143] The battery module (110) may include a plurality of battery cells (112). Each of the battery cells (112) may include an electrode assembly including a positive electrode and a negative electrode alternately and repeatedly stacked. The positive electrode and the negative electrode may be alternately and repeatedly stacked with a separator interposed therebetween. The positive electrode includes lithium metal oxide as a positive electrode active material, and the battery cell (112) may be provided as a lithium secondary battery.

[0144] A plurality of battery cells (112) each include a positive lead and a negative lead, and the positive leads and the negative leads can be joined to each other via a bus bar to define a battery module (110).

[0145] The battery module (110) can be fixed on the support plate (130). A gap filler composition according to the above-described embodiments can be applied and cured between the battery module (110) and the support plate (130) to form a gap filler (120).

[0146] The battery module (110) can be stably fixed on the support plate (130) by the gap filler (120). As described above, the gap filler (120) has stable curing characteristics and can have improved thermal conductivity characteristics.

[0147] According to exemplary embodiments, the gap filler composition has a low specific gravity and can maintain a target hardness range over a predetermined time period. Therefore, stable hardness characteristics can be maintained without compromising the overall electric vehicle process efficiency or increasing the weight of the battery pack.

[0148] Therefore, it has impact resistance and heat resistance for protecting the battery module (110) even under high temperature conditions, and can provide sufficient heat dissipation characteristics.

[0149] The gap filler (120) may be provided as a thermally conductive layer. For example, the thermal conductivity of the gap filler (120) may be about 2.5 W / m·K or more. In one embodiment, the thermal conductivity of the gap filler (120) may be 2.5 W / m·K to 6.0 W / m·K, 2.75 W / m·K to 5.0 W / m·K, or 3.0 W / m·K to 5.0 W / m·K.

[0150] The above thermal conductivity can be measured by a measuring device and method according to ISO 22007-2 standard.

[0151] In the above thermal conductivity range, heat generated during the charging / discharging process of the battery pack can be quickly transferred to the outside, thereby improving the thermal stability of the battery pack.

[0152] According to exemplary embodiments, the height of the gap filler (120) on which the battery module (110) is mounted may be 5.4 mm to 5.8 mm, or 5.4 mm to 5.7 mm. Within the above range, sufficient support stability for the battery module (110) is provided, and sufficient thermal conductivity characteristics can be realized. In addition, the occurrence of a gap between the battery module (110) and the gap filler (120) due to excessive curing can be prevented.

[0153] Hereinafter, experimental examples including specific examples and comparative examples are presented to help understand the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims. It is obvious to those skilled in the art that various changes and modifications to the examples are possible within the scope and technical idea of ​​the present invention, and it is natural that such changes and modifications fall within the scope of the appended claims.

[0154] Examples and Comparative Examples

[0155] A gap filler composition was prepared according to the ingredients and contents (parts by weight) described in Table 1 below.

[0156] Specifically, the subject composition included a first siloxane-based resin (vinyl-terminated siloxane resin), a catalyst, thermally conductive inorganic particles, and an amino-silicone-based dispersant. The crosslinking composition included a first siloxane-based resin (vinyl-terminated siloxane resin), a second siloxane-based resin (hydrogen-terminated siloxane resin), graphite particles, thermally conductive inorganic particles, and an amino-silicone-based dispersant.

[0157] The first siloxane-based resin was divided and included in the main composition and the crosslinking composition at a weight ratio of about 2:1. The thermally conductive inorganic particles were divided and included in the main composition and the crosslinking composition at a weight ratio of about 1.2:1. The amino-silicone-based dispersant was divided and included in the main composition and the crosslinking composition at a weight ratio of about 2:1.

[0158] The above crosslinking composition further includes a crosslinking agent having a hydrogen-terminated siloxane resin structure.

[0159] Meanwhile, in Example 10 and Comparative Example 5, alumina particles having an average particle diameter (D50) of about 60 μm and surface-treated with an alkylsilane agent (hexyltrimethoxysilane) were included as thermally conductive inorganic particles.

[0160] The subject composition and the crosslinking composition were prepared by including the components of Table 1 as described above, placing them in a paste mixer, mixing and stirring them at 600 rpm / 500 rpm for 3 minutes, and then defoaming them in a vacuum at 1000 rpm / 100 rpm for 10 minutes.

[0161]

[0162] Classification 1 Siloxane resin (A-1) 2 Siloxane resin (B-1) Crosslinking agent (C-1) Dispersing agent Thermally conductive inorganic particles (E-1) Graphite particles (F-1) Catalyst (G-1) D-1 D-2 Example 18.284.090.120.34-81.006.000.17 Example 28.284.090.120.34-71.0016.000.17 Example 38.284.090.120.34-83.004.000.17 Example 48.264.050.120.40-81.006.000.17 Example 58.324.090.120.30-81.006.000.17 Example 68.444.170.120.10-81.006.000.17 Example 713.036.260.200.34-74.006.000.17 Example 88.513.860.120.34-67.0020.000.17 Example 98.393.980.120.34-85.002.000.1 7Example 108.284.090.120.34-81.00(E-2)6.000.17Example 116.373.000.120.3489.001.000.17Example 123.872.500.120.3494.001.000.17Example 137.633.740.120.34-70.0018.000.17Example 147.633.740.120.34-82 .006.000.17Comparative Example 17.633.740.120.34-88.00-0.17Comparative Example 28.284.090.120.34-87.00-0.17Comparative Example 38.284.090.12-0.3481.006.000.17Comparative Example 48.484.230.12--81.006.000.17Comparative Example 53.001.370.120.34-95.00-0.17

[0163] The specific ingredients listed in Table 1 are as follows.

[0164] A-1) First siloxane resin

[0165] Polydimethylsiloxane resin with a viscosity of 270 cps and vinyl groups at both ends (see Chemical Formula 1)

[0166] B-1) Second siloxane resin

[0167] Polydimethylsiloxane resin with a viscosity of 500 cps and hydrogenated at both ends (see Chemical Formula 2)

[0168] C-1) Crosslinking agent

[0169] Polydimethylsiloxane resin hydrogenated at both ends with a viscosity of 65 cps (see Chemical Formula 3)

[0170] D-1) Amino-silicone dispersant (see general formulas 1 and 2): amine value 36 mgKOH / g

[0171] D-2) Hydroxyl group-containing silicone dispersant (BYK 1799)

[0172] E-1) Thermally conductive inorganic particles

[0173] Aluminum hydroxide particles (D50: 5㎛)

[0174] E-2) Surface-treated thermally conductive inorganic particles

[0175] Alumina particles (D50: 60㎛) surface-treated with alkyl silane (hexyltrimethoxysilane)

[0176] F-1) Graphite particles

[0177] Natural spherical graphite (D50: 15㎛)

[0178] G-1) Catalyst

[0179] Pt / Si2O combined catalyst (Pt / (Si+O) weight ratio: 1.35)

[0180]

[0181] Experimental example

[0182] (1) Specific gravity measurement

[0183] The subject composition and crosslinking composition of the examples and comparative examples were mixed at a mass ratio of 1:1 using a two-component cartridge to prepare a gap filler composition. The specific gravity of the gap filler composition was measured according to Test Method A of ASTM D792.

[0184] Specifically, the weight of each composition and the weight of the composition in water were measured according to the above specifications, and the specific gravity was calculated through the difference in the measured weights.

[0185] (2) Thermal conductivity measurement

[0186] The subject composition and crosslinking composition of the examples and comparative examples were mixed at a mass ratio of 1:1 using a two-component cartridge and cured to form a resin layer.

[0187] The thermal conductivity of the above resin layer was measured using a hot disk measuring device according to the ISO 22007-2 standard. Specifically, a numerical layer measuring 20 mm in length and width and 6.0 mm in thickness was formed, and the average value was calculated after a total of three measurements.

[0188] (3) Viscosity measurement

[0189] The subject composition and crosslinking composition of the examples and comparative examples were mixed at a mass ratio of 1:1 using a two-component cartridge to prepare a gap filler composition. The viscosity of the gap filler composition over time was measured using a viscoelasticity measuring instrument (Advanced Rheometic Expansion System) (Brookfield, DV2T Rheometer). (Measurement conditions: 20 rpm / 25°C, Gap 5 mm).

[0190] The evaluation results are shown in Table 2 below.

[0191] Classification Specific gravity Thermal conductivity (W / m K) Viscosity (Pa s) Manufacturing date 1 day 2 days 3 days 4 days 12.003.20359369374374372 Example 22.004.30830841852851850 Example 32.003.00342362371368378 Example 42.003.2033134535535 6353Embodiment 52.003.20546568581584579Embodiment 62.003.156216597999511250Embodiment 71.801.90212248252250252Embodiment 82.004.5010431090113211581233Embodiment 92.002.45340358362368375Embodiment Example 102.703.20342348356371380 Example 112.103.0081986592510651385 Example 122.203.1010231098125313031348 Example 132.004.50946992103410881178 Example 142.053.2565167970173479 5Comparative Example 12.002.40332349362380408Comparative Example 22.002.40313325329328330Comparative Example 32.003.20976956154019951956Comparative Example 42.003.209461285156818982034Comparative Example 52.302.6010591162120412431367

[0192] Referring to Tables 1 and 2, examples including thermally conductive inorganic particles, graphite particles, and amino-silicon-based dispersants provided stable viscosity stability while maintaining a low specific gravity of 3 or less, or 2.20 to 1.5; and a thermal conductivity of 2.50 W / m·K or more, or 3.0 W / m·K to 4.50 W / m·K.

[0193] In Example 6, where the amount of amino-silicone dispersant was relatively low, the viscosity change of the composition over time was high, and it was confirmed that the viscosity stability of the composition was somewhat lowered compared to other examples.

[0194] In Example 7, which had a relatively low content of inorganic filler including thermally conductive inorganic particles and graphite particles, the thermal conductivity was relatively low compared to other examples.

[0195] In Example 8, where the content of graphite particles was relatively high, the viscosity of the composition was higher than in the other examples. In Example 9, where the content of graphite was relatively low, the thermal conductivity of the composition was somewhat lower even though the content of the inorganic filler including thermally conductive inorganic particles and graphite particles was the same as in Example 1.

[0196] In Example 10, where surface-treated alumina particles were used, the composition specific gravity was somewhat increased compared to other examples.

[0197] In Examples 11 and 12, where the content of thermally conductive inorganic particles was relatively high, the viscosity of the composition was relatively high compared to other examples.

[0198] In Examples 8 and 13, where the content of graphite particles was relatively high, the thermal conductivity of the composition was relatively high compared to other examples, but the viscosity was high, so the storage stability was somewhat reduced.

[0199] In Comparative Examples 1, 2 and 5, which did not contain graphite particles, the thermal conductivity of the composition was significantly reduced.

[0200] In Comparative Example 3, where a hydroxyl-silicone-based dispersant was used instead of an amino-silicone-based dispersant, and in Comparative Example 4, where an amino-silicone-based dispersant was not used, the flowability and viscosity stability of the composition were significantly reduced due to side reactions with the surface of the thermally conductive inorganic particles.

[0201] In Comparative Example 5, which did not include graphite particles and contained only a large amount of thermally conductive inorganic particles, thermal conductivity was reduced even though graphite particles were used and the content of the inorganic filler including the thermally conductive inorganic particles and graphite particles was the same as in Example 12.

Claims

1. Siloxane resin; Filler comprising thermally conductive inorganic particles and graphite particles; catalyst; and Contains an amino-silicon dispersant, The content of the above thermally conductive inorganic particles is 65 wt% to 95 wt% of the total weight of the composition, A gap filler composition, wherein the content of the graphite particles is 1 wt% to 20 wt% of the total weight of the composition.

2. A gap filler composition according to claim 1, wherein the content of the thermally conductive inorganic particles is 71 wt% to 89 wt% of the total weight of the composition.

3. A gap filler composition according to claim 1, wherein the content of the graphite particles is 4 wt% to 16 wt% of the total weight of the composition.

4. A gap filler composition according to claim 1, wherein the content of the filler is greater than 80 wt% and less than or equal to 95 wt% of the total weight of the composition.

5. A gap filler composition according to claim 1, wherein the content of the amino-silicone dispersant is 0.1 wt% to 3 wt% of the total weight of the composition.

6. A gap filler composition according to claim 1, wherein the thermally conductive inorganic particles include aluminum hydroxide particles.

7. A gap filler composition according to claim 6, wherein the aluminum hydroxide particles are particles that are not surface-treated with an alkyl group or an alkylsilane group.

8. A gap filler composition according to claim 1, wherein the graphite particles include at least one selected from the group consisting of expanded graphite, expanded graphite, and spheroidal graphite.

9. A gap filler composition according to claim 8, wherein the spherical graphite has an average particle diameter of 1 ㎛ to 50 ㎛.

10. A gap filler composition according to claim 1, wherein the siloxane-based resin comprises a first siloxane-based resin including an unsaturated terminal group and a second siloxane-based resin including a saturated terminal group.

11. A gap filler composition according to claim 10, wherein the siloxane-based resin further comprises a crosslinking agent including a siloxane-based resin having methyl groups bonded to silicon atoms at both terminals.

12. A gap filler composition having a specific gravity of 3 or less according to claim 1.

13. A gap filler composition according to claim 1, having a viscosity of 850 Paㆍs or less at 25°C.

14. Multiple battery modules; Support plate; and A battery pack comprising a gap filler formed using the gap filler composition of claim 1 between the battery modules and the support plate.

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