KR102411610B1 - Curable Resin Composition - Google Patents

Abstract

The present application relates to a curable resin composition having excellent heat dissipation performance, excellent low-temperature impact, low load during the injection process, and excellent storage stability at the same time. The present application also relates to a battery module having excellent heat dissipation performance to which the curable resin composition is applied.

Description

Curable Resin Composition

This application relates to a curable resin composition.

In order to improve the mileage of electric vehicles, high integration of battery cells is required, and in order to reduce the high temperature heat generated by the high integration, it must have excellent cooling performance at the same time. For excellent cooling performance, an inorganic heat dissipation filler was highly filled in the curable resin composition.

However, when the inorganic heat dissipation filler is highly filled, there is a problem in that it is vulnerable to low-temperature impact conditions. In addition, when the inorganic heat dissipation filler is highly filled, there is a disadvantage in that the load is increased during the injection process and thus productivity is lowered, and when the viscosity is lowered to improve productivity, storage stability may be deteriorated.

Therefore, as a resin composition applied to a battery module, a curable resin composition that is excellent in low-temperature impact, has a low load during the injection process and at the same time has excellent storage stability is required.

Korean Patent Publication No. 2016-0105354

An object of the present application is to provide a curable resin composition having excellent heat dissipation performance and excellent low-temperature impact, a low load during the injection process, and excellent storage stability at the same time. Another object of the present application is to provide a battery module having excellent heat dissipation performance to which the curable resin composition is applied.

Among the physical properties mentioned in this specification, when the measured temperature affects the result, unless otherwise specified, the corresponding physical property is a physical property measured at room temperature. The term ambient temperature is the natural temperature, either warmed or not reduced, usually any temperature within the range of about 10°C to 30°C, or on the order of about 23°C or about 25°C. In addition, unless otherwise specified in this specification, the unit of temperature is °C.

Among the physical properties mentioned in this specification, when the measured pressure affects the result, unless otherwise specified, the corresponding physical property is a physical property measured at normal pressure. The term atmospheric pressure refers to a natural temperature that has not been pressurized or depressurized, and usually about 1 atmosphere is referred to as atmospheric pressure.

In an example related to the present application, the present application relates to a curable resin composition used for a battery module or a battery pack. Specifically, the curable resin composition according to the present application may be a two-component resin composition injected into the case of the battery module and used to contact one or more battery cells present in the battery module to fix the battery cells in the battery.

The curable resin composition of the present application includes a main resin, a curing agent, an inorganic filler, and a load reducing agent, and A _ij of the following general formula 1 satisfies 0.11 or more.

[General formula 1]

A _ij = min(1, exp(-Δμ _ij /RT))

In the above general formula 1, A _ij is the affinity of the load reducing agent for the main resin, Δμ _ij is the mixing energy of the main resin for the load reducing agent, R is a gas constant, and T is the absolute temperature.

In Formula 1, Δμ _ij , that is, the mixing energy of the main resin with respect to the load reducing agent can be calculated by applying the COSMO-RS (conductorlikescreening model for real solvent) theory. Specifically, it can be derived using COSMOtherm, a COSMO-RS related program.

A _ij of Formula 1, that is, the affinity of the load reducing agent to the main resin may be 0.11 or more, and in another example, may be about 0.12 or more, 0.13 or more, 0.14 or more, or about 0.15 or more.

A curable resin composition in which A _ij of General formula 1 is 0.11 or more can improve storage stability.

The curable resin composition may be prepared by mixing the main resin composition and the curing agent composition. The main resin composition includes a main resin and an inorganic filler, and the curing agent composition includes a curing agent and an inorganic filler.

It is advantageous that the main resin composition before mixing into the curable resin composition is maintained in a mixed state for a long time without separation of the resin component and the inorganic filler. In addition, it is advantageous for the curing agent composition to be maintained in a mixed state for a long time without separation of the resin component and the inorganic filler.

the resin component and inorganic filler of the main resin composition; Alternatively, when the resin component of the curing agent composition and the inorganic filler are not separated and maintained in a mixed state for a long time, it can be considered that the storage stability is excellent.

When the curable resin composition of the present application has A _ij of 0.11 or more, the storage stability of the curable resin composition may be improved. Specifically, in the case of a curable resin composition satisfying Formula 1, when the main resin composition or the curing agent composition is stored in a sealed glass container at about 25° C. and about 50% RH, the resin component and the inorganic filler are separated for about 90 days or more. It can be kept in a mixed state.

As an example, the affinity of the load reducing agent to the curing agent included in the curable resin composition may satisfy 0.11 or more. That is, both the affinity of the main resin and the curing agent to the load reducing agent may satisfy General Formula 1, and in this case, the storage stability of the curable resin composition may be further improved.

As the main resin included in the curable resin composition in the present application, a silicone resin, a polyol resin, an epoxy resin, or an acrylic resin may be used. Meanwhile, as the curing agent, a siloxane compound, an isocyanate compound, or an amine compound may be used.

As an example, the main resin may be a polyol resin, and the curing agent may be an isocyanate.

The polyol may be amorphous or may be an ester polyol having sufficiently low crystallinity. In the present specification, "amorphous" means a case in which the crystallization temperature (Tc) and the melting temperature (Tm) are not observed in a differential scanning calorimetry (DSC) analysis to be described later. At this time, the DSC analysis can be performed within the range of -80 to 60 °C at a rate of 10 °C / min, for example, the temperature is increased from 25 °C to 60 °C at the above rate, and then the temperature is reduced to -80 °C again, It can be made in a way that the temperature is raised to 60 ℃ again. In addition, in the above, "sufficiently low crystallinity" means that the melting point (Tm) observed in the DSC analysis is less than 15°C, about 10°C or less, 5°C or less, 0°C or less, -5°C or less, -10 It means a case of about ℃ or less or about -20℃ or less. At this time, the lower limit of the melting point is not particularly limited, but, for example, the melting point may be about -80°C or more, -75°C or more, or about -70°C or more. When the polyol is crystalline or does not satisfy the above melting point range, when crystallinity is strong (at room temperature), the difference in viscosity according to temperature tends to increase, so the dispersion degree of the filler and the viscosity of the final mixture in the process of mixing the filler and the resin may have a detrimental effect on In addition, it may become difficult to satisfy physical properties such as cold resistance, heat resistance, and water resistance required in the curable resin composition for a battery module.

In one example, the polyol may be, for example, a carboxylic acid polyol or a caprolactone polyol.

The carboxylic acid polyol may be formed by reacting a component including a carboxylic acid and a polyol (eg, a diol or a triol), and the caprolactone polyol includes caprolactone and a polyol (eg, a diol or a triol). It can be formed by reacting the components. In this case, the carboxylic acid may be a dicarboxylic acid.

In one example, the polyol may be a polyol represented by the following Chemical Formula 1 or 2.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, X is a unit derived from a carboxylic acid, and Y is a unit derived from a polyol. The unit derived from the polyol may be, for example, a triol unit or a diol unit. In addition, n and m may be any number, for example, n is a number within the range of 2 to 10, m is a number within the range of 1 to 10, A ₁ and A ₂ Each independently has 1 to 14 carbon atoms is alkylene within the range of

As used herein, the term “carboxylic acid-derived unit” may refer to a portion excluding a carboxyl group in a carboxylic acid compound. Similarly, as used herein, the term “polyol-derived unit” may refer to a portion of a polyol compound structure excluding a hydroxyl group.

That is, when the hydroxyl group of the polyol and the carboxyl group of the carboxylic acid react, water (H ₂ O) molecules are desorbed by the condensation reaction to form an ester bond. As such, when the carboxylic acid forms an ester bond by the condensation reaction, the carboxylic acid-derived unit may mean a portion of the carboxylic acid structure that does not participate in the condensation reaction. In addition, the polyol-derived unit may refer to a portion of the polyol structure that does not participate in the condensation reaction.

In addition, Y in Formula 2 also represents a portion excluding the ester bond after the polyol forms an ester bond with caprolactone. That is, when the polyol-derived unit, Y, in Formula 2 forms an ester bond between the polyol and caprolactone, it may mean a portion of the polyol structure that does not participate in the ester bond. The ester bonds are shown in Formulas 1 and 2, respectively.

On the other hand, when the polyol-derived unit of Y in the formula is a unit derived from a polyol including three or more hydroxyl groups, such as a triol unit, a branched structure may be implemented in the Y portion in the formula structure.

In Formula 1, the type of the carboxylic acid-derived unit of X is not particularly limited, but in order to secure desired physical properties, a fatty acid compound, an aromatic compound having two or more carboxyl groups, an alicyclic compound having two or more carboxyl groups, and 2 It may be a unit derived from at least one compound selected from the group consisting of aliphatic compounds having at least two carboxyl groups.

The aromatic compound having two or more carboxyl groups may be, for example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid or tetrachlorophthalic acid.

The alicyclic compound having two or more carboxyl groups may be, for example, tetrahydrophthalic acid or hexahydrophthalic acid or tetrachlorophthalic acid.

In addition, the aliphatic compound having two or more carboxyl groups is, for example, oxalic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, malic acid, glutaric acid, malonic acid, pimelic acid, suberic acid, 2,2-dimethyl succinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylglutaric acid, maleic acid, fumaric acid or itaconic acid.

Considering the low glass transition temperature in the range to be described later, an aliphatic carboxylic acid-derived unit may be preferable rather than an aromatic carboxylic acid-derived unit.

On the other hand, in Formulas 1 and 2, the type of the polyol-derived unit of Y is not particularly limited, but in order to secure desired physical properties, from the group consisting of an alicyclic compound having two or more hydroxyl groups and an aliphatic compound having two or more hydroxyl groups may be derived from one or more selected compounds.

The alicyclic compound having two or more hydroxyl groups may be, for example, 1,3-cyclohexanedimethanol or 1,4-cyclohexanedimethanol.

In addition, the aliphatic compound having two or more hydroxyl groups is, for example, ethylene glycol, propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,2-ethylhexyldiol, 1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol, glycerin or trimethylol It may be propane.

Meanwhile, in Formula 1, n is an arbitrary number, and the range may be selected in consideration of desired physical properties of the curable resin composition or the cured resin layer thereof. For example, n can be about 2 to 10 or 2 to 5.

In addition, in Formula 2, m is an arbitrary number, and the range may be selected in consideration of desired physical properties of a curable resin composition or a resin layer that is a cured product thereof. For example, m is about 1 to 10 or 1 to 5 can be

When n and m in Formulas 1 and 2 are out of the above ranges, the crystallinity of the polyol may be strengthened and adversely affect the injection processability of the composition.

In Formula 2, A ₁ and A ₂ are each independently alkylene having 1 to 14 carbon atoms. The number of carbon atoms may be selected in consideration of desired physical properties of the curable resin composition or a resin layer that is a cured product thereof.

The molecular weight of the polyol may be adjusted in consideration of viscosity, durability, or adhesion, for example, in the range of about 300 to about 2,000. Unless otherwise specified, in the present specification, "molecular weight" may be a weight average molecular weight (Mw) measured using Gel Permeation Chromatograph (GPC). If out of the above range, the reliability of the resin layer after curing may be poor or problems related to volatile components may occur.

In the present application, the type of isocyanate included in the curing agent is not particularly limited, but a non-aromatic isocyanate compound not including an aromatic group may be used to secure desired physical properties. When an aromatic isocyanate is used, it may be difficult to satisfy the load value and viscosity of the curable resin composition, which will be described later, because the reaction rate is too fast and the glass transition temperature may be high.

Examples of the non-aromatic isocyanate compound include aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate methyl, ethylene diisocyanate, propylene diisocyanate or tetramethylene diisocyanate. ; alicyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, bis(isocyanatemethyl)cyclohexane diisocyanate or dicyclohexylmethane diisocyanate; Or any one or more of the above-mentioned carbodiimide-modified polyisocyanate or isocyanurate-modified polyisocyanate; etc. may be used. Also, mixtures of two or more of the compounds listed above may be used.

The curable resin composition of the present application includes an inorganic filler. The inorganic filler may be a thermally conductive filler. In the present application, the term thermally conductive filler refers to a material having a thermal conductivity of about 1 W/mK or more, about 5 W/mK or more, about 10 W/mK or more, or about 15 W/mK or more. The thermal conductivity of the thermally conductive filler may be about 400 W/mK or less, about 350 W/mK or less, or about 300 W/mK or less. The kind of thermally conductive filler that can be used is not particularly limited, and for example, aluminum oxide (alumina: Al ₂ O ₃ ), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si ₃ N ₄ ), carbide Ceramic particles such as silicon (SiC) beryllium oxide (BeO), zinc oxide (ZnO), aluminum hydroxide (Al(OH) ₃ ), or boehmite may be used.

In addition to the above fillers, various types of fillers may be used. For example, in order to secure the insulating properties of the cured resin layer of the curable resin composition, the use of a carbon filler such as graphite may be considered. Alternatively, fillers such as, for example, fumed silica, clay or calcium carbonate (CaCO ₃ ) may be used.

The form or ratio of the filler is not particularly limited, and the viscosity of the curable resin composition, the curing rate of the curable resin composition, the possibility of sedimentation in the cured resin layer of the curable resin composition, the desired thermal resistance or thermal conductivity, insulation, filling It may be appropriately adjusted in consideration of the effect, dispersibility or storage stability. In general, as the size of the filler increases, the viscosity of the composition including the same increases, and the possibility that the filler settles in the resin layer to be described later increases. Also, the smaller the size, the higher the thermal resistance tends to be. Therefore, in consideration of the above points, a filler of an appropriate type and size may be selected, and if necessary, two or more types of fillers may be used together. In addition, it is advantageous to use a spherical filler in consideration of the amount to be filled, but a filler in the form of needles or plates may also be used in consideration of network formation or conductivity.

In one example, the curable resin composition may use fillers having different average particle diameters. In the present application, the average particle diameter is the particle diameter (direct median) at 50% cumulative by volume of the particle size distribution. The point at which the cumulative value becomes 50% on the cumulative curve with the total volume as 100% after obtaining the particle size distribution on the volume basis. is the particle diameter of The average particle diameter (or D50) as described above may be measured by a laser diffraction method. Accordingly, the different average particle diameter may mean inorganic fillers having different particle diameters at 50% of the cumulative volume based on the particle size distribution. In one embodiment, the inorganic filler of the present application may use an inorganic filler having at least three different average particle diameters.

The average particle diameter of the inorganic filler may be in the range of about 0.001 μm to about 100 μm. The average particle diameter of the filler may be about 0.01 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, or about 6 μm or more in another example, 95 μm or less, 90 μm or less, 85 μm or less, 80 μm or less, 75 μm or less, 70 μm or less, 65 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, or about 10 μm or less.

On the other hand, when inorganic fillers having at least three different average particle diameters are used, inorganic fillers having three different average particle diameters among the inorganic fillers within the range of the average particle diameter, that is, from about 0.001 μm to about 100 μm, are used for the physical properties of the curable resin composition It can be appropriately selected and used in consideration of such factors.

In order to obtain excellent heat dissipation performance, it may be considered that a high content of the thermally conductive filler is used. For example, it may be included in a ratio of about 70 parts by weight to 95 parts by weight relative to 100 parts by weight of the curable resin composition. As another example, the curable resin composition may be included in an amount of about 75 parts by weight or more, or about 80 parts by weight or more, and may be included in a ratio of about 90 parts by weight or less, based on 100 parts by weight of the curable resin composition.

When the content of the inorganic filler exceeds about 95 parts by weight based on 100 parts by weight of the curable resin composition, it is disadvantageous to satisfy the load value to be described later, and storage stability may deteriorate. On the other hand, when the content of the inorganic filler is less than about 70 parts by weight based on 100 parts by weight of the curable resin composition, the thermal conductivity is low, and thus a battery module to be described later including the same may be disadvantageous in securing the desired heat dissipation performance.

Since the inorganic filler is included in the curable resin composition in a ratio within the above range, it is possible to improve the overload of injection equipment and improve storage stability, and the cured product of the curable resin composition has high thermal conductivity, so a battery to be described later including it The module is advantageous in securing excellent heat dissipation performance.

In one example, the inorganic filler of the present application may have a moisture content of about 1,000 ppm or less. The moisture content can be measured with a Karl Fischer titrator (KR831) under the conditions of 10% relative humidity and 5.0 or less drift. In this case, the moisture content may be an average moisture content with respect to all inorganic fillers used in the curable resin composition. In the present application, an inorganic filler satisfying the above conditions may be selectively used, or after drying the inorganic filler to be used in an oven at a temperature of about 200° C., the moisture content of the inorganic filler may be adjusted to satisfy the moisture content range. may be In another example, the upper limit of the moisture content of the inorganic filler may be about 800 ppm or less, 600 ppm or less, or about 400 ppm or less, and the lower limit thereof may be about 100 ppm or more or about 200 ppm or more.

The curable resin composition of the present application includes a load reducing agent.

In the present application, the load reducing agent may mean a material capable of reducing the load applied to the injection equipment for injecting the curable resin composition into the battery module case.

The load reducing agent according to the present application may have a viscosity of 3,000 cP or less measured at 25° C. using a Brookfield LV type viscometer. In another example, the viscosity of the load reducing agent may be about 2,800 cP or less, 2,600 cP or less, 2,400 cP or less, or about 2,300 cP or less, and may be about 10 cP or more, 50 cP or more, or about 100 cP or more.

When the viscosity of the load reducing agent exceeds 3,000 cP, since the viscosity of the curable resin composition by the load reducing agent may be increased, the effect of reducing the load of the injection equipment may be reduced.

When the viscosity of the load reducing agent satisfies 3,000 cP or less, the load of the injection equipment for injecting the curable resin composition may be reduced. In addition, it may be more advantageous to satisfy the aforementioned general formula (1).

As an example, the load reducing agent is not particularly limited as long as it is liquid at room temperature and satisfies the above-mentioned general formula 1, and a known material may be used.

For example, the load reducing agent may be an aliphatic compound that is liquid at room temperature and has two or more ester groups in the molecule.

The aliphatic compound having two or more ester groups in the molecule may be castor oil or a compound represented by the following Chemical Formulas 3, 4 or 5.

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, R ₁ and R ₂ may be the same or different, and each independently represents an alkyl group having 1 to 8 carbon atoms that is unsubstituted or substituted with at least one alkyl group having 1 to 4 carbon atoms, R ₃ , R ₄ and R ₅ may be the same or different and are each independently an alkylene group having 1 to 8 carbon atoms substituted or unsubstituted with at least one alkyl group having 1 to 4 carbon atoms, and R ₆ and R ₇ may be the same or different and each independently is an aromatic hydrocarbon unsubstituted or substituted with at least one C 1 to C 4 alkyl group.

In Formulas 3 to 5, the meaning that R ₃ , R ₄ and R ₅ are the same or different may mean that R3, R ₄ and R ₅ are all the same, some are the same and some are different, or all are different. have.

The aromatic hydrocarbon in R ₆ or R ₇ of Formula 5 is not particularly limited, but may be, for example, benzene, naphthalene, or anthracene.

The compound represented by Formula 3 is, for example, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, and diethyl malonate (diethyl). adipate), dipropyl adipate, dibutyl adipate, dipentyl adipate, dihexyl adipate, bis(2-methylhexyl) adipate (2-methylhexyl) adipate), bis(2-ethylhexyl) adipate (bis(2-ethylhexyl) adipate), bis(2,5-dimethylhexyl) adipate) or bis(2-ethyl-5-methylheptyl) adipate.

The compound represented by Formula 4 is, for example, dimethyl '-methylene diadipate, dimethyl'-propane-1,3-diadipate (dimethyl'-propane-1,3-diyl diadipate). ), diethyl'-propane-1,3-diyl diadipate, dihexyl'-propane-1,3-diyl diadipate (dihexyl'-propane-) 1,3-diyl diadipate), bis(2-ethylhexyl)'-propane-1,3-diyl diadipate (bis(2-ethylhexyl)'-propane-1,3-diyl diadipate) or 'butane-1 , 3-diyl bis (2-ethylhexyl) diadipate ('-butane-1,3-diyl bis (2-ethylhexyl) diadipate) may be.

The compound represented by Formula 5 is, for example, oxybis(methylene) dibenzoate, 1-(1-(benzoyloxy)propan-2-yloxy)propan-2-yl benzoate. (1-(1-(benzoyloxy)propan-2-yloxy)propan-2-yl benzoate), oxybis(methylene) di-2-naphthoate, or 1-( 1-(2-naphthoyloxy)propan-2-yloxy)propan-2-yl benzoate (1-(1-(2-naphthoyloxy)propan-2-yloxy)propan-2-yl 2-naphthoate)yl can

When using the castor oil or the compound represented by Chemical Formulas 3 to 5 as the load reducing agent, it may be more advantageous to satisfy General Formula 1 above. Therefore, the load of the curable resin composition is low during the injection process, so injection is easy, and storage stability can be improved.

As an example, the load reducing agent may be included in an amount of less than 30 parts by weight based on 100 parts by weight of the resin component of the curable resin composition. In another example, based on 100 parts by weight of the resin component of the curable resin composition, about 28 parts by weight or less, 26 parts by weight or less, 24 parts by weight or less, 20 parts by weight or less, 18 parts by weight or less, 16 parts by weight or less, 14 parts by weight or less, or about 12 parts by weight or less It may contain up to about 2 parts by weight, 4 parts by weight or more, or about 6 parts by weight or more.

When the load reducing agent contains 30 parts by weight or more based on 100 parts by weight of the resin component of the curable resin composition, physical properties such as storage stability and adhesion may be reduced, and 2 parts by weight of the load reducing agent relative to 100 parts by weight of the resin component of the curable resin composition When it contains less than, it may be disadvantageous in satisfying the load value of the curable resin composition to be described later.

As an example, the curable resin composition may have a glass transition temperature (Tg) of 25° C. or less. In another example, it may be about 20 ° C or less or about 15 ° C or less, about -70 ° C or more, -65 ° C or more, -60 ° C or more, -55 ° C or more, -50 ° C or more, -45 ° C or more, -40 ° C or more, It may be at least -35°C or at least about -30°C.

In the present application, the glass transition temperature can be measured using a differential scanning calorimetry (DSC), Mettler.

When the glass transition temperature of the curable resin composition satisfies the above range, it is possible to provide a battery module that is stable even in low-temperature impact.

As an example, the curable resin composition may have a load value measured at room temperature immediately after mixing of less than 40 kgf. In another example, it may be less than about 38 kgf, less than 36 kgf, or less than about 34 kgf, and may be greater than about 15 kgf, greater than 20 kgf, or greater than about 25 kgf.

In the present application, the load value of the curable resin composition may be measured using a mixer in which a cartridge and a mixer are combined. 1 is a cross-sectional view showing an exemplary mixer that can be applied in the present application. The mixer (1) includes two cartridges (2) and one mixer (5), and the cartridge may have a pressing means (3). In the present application, the cartridge 2 is not particularly limited, and a known cartridge may be used as long as it can accommodate the main resin composition including the main resin and inorganic filler and the curing agent composition including the curing agent and the inorganic filler. In one embodiment, the diameter of the cartridge accommodating the main resin composition or curing agent composition is about 15 mm to about 20 mm circular, and the diameter of the discharge portion of the first discharge parts 4a and 4b for discharging the main resin composition or curing agent composition is It has a circular shape of about 2 mm to about 5 mm, a height of about 80 mm to about 300 mm, and a total volume of about 10 ml to about 100 ml. The cartridges 2a, 2b may have pressing means 3a, 3b. The pressing means (3a, 3b) is not particularly limited, a known pressing means may be used. For example, the pressing means may use a texture analyzer (TA). The pressing means (3a, 3b) may press the cartridge (2a, 2b) to discharge the main resin composition and the curing agent composition inside the cartridge through the mixer (5). The pressing speed of the pressing means 3a and 3b may be about 0.01 to about 1 mm/s. For example, the pressing speed may be about 0.01 mm/s or more, 0.05 mm/s or more, or about 0.1 mm/s or more, and about 1 mm/s or less, 0.8 mm/s or less, 0.6 mm/s or less, 0.4 mm/s or less. s or less or about 0.2 mm/s or less.

Meanwhile, the mixer 5 is not particularly limited, and a known mixer may be used. For example, the mixer may be a static mixer. In one embodiment, the static mixer 5 includes two receiving portions 6a and 6b for receiving the main resin composition and the curing agent composition from the two cartridges 2a and 2b, respectively, and the static mixer 5. It has one second discharge part 7 for discharging the mixed resin composition, and the size of the receiving parts 6a and 6b is a circular shape with a diameter of about 2 mm to about 5 mm, respectively, and the diameter of the second discharge part 7 has a circular shape of about 1 mm to about 3 mm, and the number of elements may be about 5 to about 20.

On the other hand, the capacity of the mixer may have a capacity satisfying the range of the following general formula (4).

[General formula 4]

V < t2/td * Q

In Formula 4, V is the capacity of the static mixer, t2 is the time for doubling the viscosity of the resin composition, td is the injection process time, and Q is the injection amount per process unit time. When the capacity of the static mixer is large compared to the time (t2) for which the viscosity is doubled, the residence time exceeds the amount per unit process and the viscosity increases, and if the process speed is slow or severe, the resin composition is cured and the mixer is likely to be blocked.

Therefore, the load value of the curable resin composition according to the present application is to inject the main resin composition and the curing agent composition into the cartridge, respectively, and pressurize the main resin composition and the curing agent composition with a mixer by pressing at a constant speed of about 0.1 mm / s with a pressing means, , When the curable resin composition, which is the mixture, is discharged through the discharge part of the mixer, the force applied to the pressing means is measured from the time the curable resin composition is discharged, and the maximum value at the point where the force becomes the maximum value was taken as the load value. The maximum value is the maximum value initially confirmed in the above process, and is the maximum value at the initial point where the applied force increases and then decreases, or the maximum value at the point where the applied force increases and then does not increase any more.

If the load value measured at room temperature within 60 seconds after mixing the curable resin composition is 40 kgf or more, overload occurs in the injection equipment of the curable resin composition, thereby shortening the life of the injection equipment or the productivity of the battery module may decrease. In addition, when the load value is less than 15 kgf, overflow may occur or storage stability of the resin composition may be deteriorated after the curable resin composition is charged into the battery module.

As an example, the curable resin composition is measured at a point of 2.5/s when measured in a shear rate range of 0.01 to 10.0/s using a rheometer (ARES) at room temperature within 60 seconds after mixing The applied viscosity may be 250,000 cP to 350,000 cP.

When the curable resin composition satisfies the viscosity in the above range, it is more advantageous to satisfy the load value of the curable resin composition described above.

The present application also relates to a battery module. The module includes a module case and a battery cell. The battery cell may be accommodated in the module case. One or more battery cells may be present in the module case, and a plurality of battery cells may be accommodated in the module case. The number of battery cells accommodated in the module case is not particularly limited as it is adjusted according to the use or the like. The battery cells accommodated in the module case may be electrically connected to each other.

The module case may include at least a side wall and a lower plate forming an internal space in which the battery cell can be accommodated. In addition, the module case may further include an upper plate for sealing the inner space. The side wall, the lower plate, and the upper plate may be integrally formed with each other, or the module case may be formed by assembling the separate side walls, the lower plate, and/or the upper plate, respectively. The shape and size of the module case are not particularly limited, and may be appropriately selected depending on the purpose or the shape and number of battery cells accommodated in the inner space.

In the above, the terms upper plate and lower plate are terms of a relative concept used to distinguish between at least two plates constituting the module case. That is, it does not mean that the upper plate necessarily exists in the upper part and the lower plate necessarily exists in the lower part in an actual use state.

2 is a view showing an exemplary module case 10, and is an example of a box-shaped case 10 including one lower plate 10a and four side walls 10b. The module case 10 may further include an upper plate 10c for sealing the inner space.

3 is a schematic view of the module case 10 of FIG. 3 in which the battery cell 20 is accommodated, as viewed from above.

A hole may be formed in the lower plate, the side wall, and/or the upper plate of the module case. The hole may be an injection hole used to inject a material for forming the resin layer, that is, the above-mentioned curable resin composition, when the resin layer is formed by an injection process. The shape, number, and position of the holes may be adjusted in consideration of injection efficiency of the resin layer forming material. In one example, the hole may be formed in at least the lower plate and/or the upper plate.

An observation hole may be formed at the ends of the upper plate and the lower plate in which the injection hole is formed. This observation hole, for example, when injecting the resin layer material through the injection hole, may be formed to observe whether the injected material is well injected to the end of the side wall, the lower plate or the upper plate. The position, shape, size, and number of the observation hole are not particularly limited as long as they are formed so as to confirm whether the injected material is properly injected.

The module case may be a thermally conductive case. The term thermally conductive case refers to a case having an overall thermal conductivity of 10 W/mk or more, or at least including a portion having the above-described thermal conductivity. For example, at least one of the aforementioned sidewall, lower plate, and upper plate may have the aforementioned thermal conductivity. In another example, at least one of the side wall, the lower plate, and the upper plate may include a portion having the thermal conductivity. For example, the battery module of the present application may include a first cured resin layer in contact with the upper plate and the battery cell, and a second cured resin layer in contact with the lower plate and the battery cell, wherein at least the second resin layer is a thermoelectric layer. It may be a conductive resin layer. Accordingly, it can be said that at least the lower plate may have thermal conductivity or include a thermally conductive portion.

a top plate, a bottom plate, and a side wall that are thermally conductive in the above; Or thermal conductivity of the region; in another example, about 20 W / mk or more, 30 W / mk or more, 40 W / mk or more, 50 W / mk or more, 60 W / mk or more, 70 W / mk or more, 80 W/mk or more, 90 W/mk or more, 100 W/mk or more, 110 W/mk or more, 120 W/mk or more, 130 W/mk or more, 140 W/mk or more, 150 W/mk or more, 160 W /mk or more, 170 W/mk or more, 180 W/mk or more, 190 W/mk or more, or about 195 W/mk or more. The higher the thermal conductivity, the more advantageous in terms of heat dissipation characteristics of the module, and the upper limit thereof is not particularly limited. In one example, the thermal conductivity is about 1,000 W/mK or less, 900 W/mk or less, 800 W/mk or less, 700 W/mk or less, 600 W/mk or less, 500 W/mk or less, 400 W/mk or less, 300 W/mk or about 250 W/mK or less, but is not limited thereto. The type of material exhibiting the above-described thermal conductivity is not particularly limited, and for example, a metal material such as aluminum, gold, silver, tungsten, copper, nickel, or platinum may be used. The module case may be entirely made of the thermally conductive material as described above, or at least a portion of the module case may be made of the thermally conductive material. Accordingly, the module case may have thermal conductivity within the above-mentioned range or may include at least one portion having the above-mentioned thermal conductivity.

In the module case, a portion having thermal conductivity within the above range may be a portion in contact with the resin layer and/or the insulating layer. In addition, the portion having the thermal conductivity may be a portion in contact with a cooling medium such as cooling water. In the case of having such a structure, heat generated from the battery cell can be effectively dissipated to the outside.

In the present application, the term battery cell refers to a single unit secondary battery including an electrode assembly and an exterior material.

The type of battery cell accommodated in the battery module case is not particularly limited, and all known various battery cells may be applied. In one example, the battery cell may be of a pouch type.

The battery module of the present application may further include a resin layer. Specifically, the battery module of the present application may include a resin layer in which the filler-containing curable resin composition is cured. The resin layer may be formed from the aforementioned curable resin composition.

The battery module may include, as the resin layer, a first cured resin layer in contact with the upper plate and the battery cell, and a second cured resin layer in contact with the lower plate and the battery cell. At least one of the first and second cured resin layers may include a cured product of the curable resin composition described above, and thus may have the predetermined adhesive strength, cold resistance, heat resistance, and insulation properties described above.

In addition, the first and second cured resin layers are thermally conductive resin layers, and the thermal conductivity of the resin layer may be about 3 W/mK or more. As another example, it may be about 3.5 W/mK or more or about 4 W/mK or more, and about 50 W/mK or less, 45 W/mk or less, 40 W/mk or less, 35 W/mk or less, 30 W/mk or less, 25 W/mk or less, 20 W/mk or less, 15 W/mk or less, 10 W/mK or less, 5 W/mK or less, 4.5 W/mK or less, or about 4.0 W/mK or less.

When the resin layer is a thermally conductive resin layer as described above, the lower plate, the upper plate, and/or the sidewall to which the resin layer is attached may be a region having the aforementioned thermal conductivity of 10 W/mK or more. In this case, the portion of the module case showing the thermal conductivity may be a portion in contact with a cooling medium, for example, cooling water. The thermal conductivity of the resin layer is, for example, a value measured according to ASTM D5470 standard or ISO 22007-2 standard. The thermal conductivity of the resin layer as described above can be secured, for example, by appropriately adjusting the filler included in the resin layer and the content ratio thereof, as described above.

In addition, the resin layer may be a flame retardant resin layer. In the present application, the term flame retardant resin layer may mean a resin layer showing a V-0 grade in UL 94 V Test (Vertical Burning Test). This ensures safety against fires and other accidents that may occur in the battery module.

In the battery module of the present application, at least one of the sidewall, the lower plate, and the upper plate in contact with the resin layer may be the aforementioned thermally conductive sidewall, lower plate, or upper plate. On the other hand, in this specification, the term contact, for example, the resin layer and the upper plate, lower plate and / or sidewall; Alternatively, it may mean a case in which the battery cells are in direct contact with each other, or another element, for example, an insulating layer, is present therebetween. In addition, the resin layer in contact with the thermally conductive sidewall, the lower plate, or the upper plate may be in thermal contact with the object. At this time, in the thermal contact, the resin layer is in direct contact with the lower plate or the like, or another element, for example, an insulating layer to be described later, exists between the resin layer and the lower plate, etc., but the other element is the It may mean a state in which heat transfer from the battery cell to the resin layer and from the resin layer to the lower plate is not prevented. The fact that the heat transfer is not hindered means that even when another element (eg, an insulating layer) exists between the resin layer and the lower plate, the total thermal conductivity of the other element and the resin layer is about 1.5 W/ mK or more, 2 W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more, or about 4 W/mK or more, or the entire resin layer and the lower plate in contact with it It means that the thermal conductivity is included within the range even if the other factors are present. The thermal conductivity of the thermal contact is about 50 W/mK or less, 45 W/mk or less, 40 W/mk or less, 35 W/mk or less, 30 W/mk or less, 25 W/mk or less, 20 W/mk or less, 15 W/mk or less, 10 W/mK or less, 5 W/mK or less, 4.5 W/mK or less, or about 4.0 W/mK or less. Such thermal contact may be achieved by controlling the thermal conductivity and/or thickness of the other element, if present.

The thermally conductive resin layer may be in thermal contact with the lower plate and the like, and may also be in thermal contact with the battery cell. Through the adoption of the above structure, the heat dissipation characteristics are secured, and the unit volume while significantly reducing the various fastening parts or cooling equipment of the module, etc., which were previously required when configuring a general battery module or a battery pack, which is an aggregate of such modules. It is possible to implement a module in which more battery cells are accommodated per unit. Accordingly, in the present application, it is possible to provide a more compact, light and high-output battery module.

In one example, the battery module may further include an insulating layer between the module case and the battery cell or between the resin layer and the module case. By adding an insulating layer, it is possible to prevent problems such as electric short circuit or fire caused by contact between the cell and the case due to an impact that may occur during use. The insulating layer may be formed using an insulating sheet having high insulating properties and thermal conductivity, or may be formed by coating or injecting an insulating material. For example, a process of forming an insulating layer may be performed before injection of the curable resin composition. A so-called TIM (thermal interface material) or the like may be applied to the formation of the insulating layer. Alternatively, the insulating layer may be formed of an adhesive material. For example, the insulating layer may be formed using a resin layer with little or no filler such as a thermally conductive filler. As a resin component that can be used to form the insulating layer, acrylic resin, olefin resin such as PVC (poly(vinyl chloride)), PE (polyethylene), epoxy resin, silicone, or EPDM rubber ((ethylene propylene diene monomer rubber) The insulating layer may have a breakdown voltage of about 5 kV/mm or more, 10 kV/mm or more, 15 kV/mm measured according to ASTM D149, but is not limited thereto. or more, it may be 20 kV/mm or more, 25 kV/mm or more, or about 30 kV/mm or more.The breakdown voltage is not particularly limited as it shows excellent insulation as the value increases. For example, the insulation The dielectric breakdown voltage of the layer may be about 100 kV/mm or less, 90 kV/mm or less, 80 kV/mm or less, 70 kV/mm or less, or about 60 kV/mm or less. It can be set in an appropriate range in consideration of insulation or thermal conductivity, for example, about 5 μm or more, 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 70 μm or more. or more, 80 μm or more, or about 90 μm or more The upper limit of the thickness is not particularly limited, for example, about 1 mm or less, 200 μm or less, 190 μm or less, 180 μm or less, 170 μm or less , 160 μm or less or about 150 μm or less.

The present application also relates to a battery pack, for example, a battery pack including two or more of the aforementioned battery modules. In the battery pack, the battery modules may be electrically connected to each other. A method of configuring a battery pack by electrically connecting two or more battery modules is not particularly limited, and any known method may be applied.

The present application also relates to a device comprising the battery module or the battery pack. Examples of the device include, but are not limited to, a vehicle such as an electric vehicle, and may include any application requiring a secondary battery as an output. For example, a method of configuring the vehicle using the battery pack is not particularly limited, and a general method may be applied.

The curable resin composition of the present application has excellent heat dissipation performance, is excellent in low-temperature impact, maintains a low load during the injection process, and has excellent storage stability. The battery module to which the curable resin composition according to the present application is applied has excellent heat dissipation performance.

1 shows an exemplary mixer for measuring a load value of a curable resin composition that can be applied in the present application.
2 shows an exemplary case that can be applied to a battery module.
3 schematically shows a form in which a battery cell is accommodated in a module case.

Hereinafter, the present application will be described in detail through Examples, but the scope of the present application is not limited by the Examples below.

Affinity of load reducer

The affinity of the load reducing agent with respect to the main resin used in Examples and Comparative Examples was calculated|required.

Specifically, the affinity was calculated through the following general formula (1).

[General formula 1]

A _ij = min(1, exp(-Δμ _ij /RT))

In the above general formula 1, A _ij is the affinity of the load reducing agent to the main resin, Δμ _ij is the mixing energy of the main resin to the load reducing agent, R is a gas constant, and T is the absolute temperature.

In Formula 1, Δμ _ij , that is, the mixing energy of the main resin with respect to the load reducing agent was calculated by applying the COSMO-RS (conductorlikescreening model for real solvent) theory. Specifically, it was derived using COSMOtherm, a COSMO-RS related program.

storage stability

A 50 mL vial was filled with the main resin composition prepared in Examples and Comparative Examples to about 40 mL, and then left for 90 days under constant temperature and humidity (25° C./50% RH) conditions. Thereafter, it was evaluated whether or not phase separation in which the curable resin composition was separated into two or more layers occurred.

[Evaluation standard]

When the thickness of the upper layer due to phase separation is 1 mm or more: ×

If phase separation does not occur or the thickness of the upper layer due to phase separation is less than 1 mm: ○

load value

The load value (kgf) of the curable resin composition was measured using the mixer 1 constructed by combining the cartridges 2a and 2b and one static mixer 5 as shown in FIG. 1 .

As for the cartridges 2a and 2b (Sulzer, AB050-01-10-01) in the mixer configured as shown in FIG. 1, the resin injection part is a circle with a diameter of 18 mm, and the discharge parts 4a and 4b are circular with a diameter of 3 mm. , the cartridges (2a, 2b) are 100mm in height and have an internal volume of 25ml. In addition, as the static mixer 5 (Sulzer, MBH-06-16T), a circular discharge part 7 having a diameter of 2 mm was used. The static mixer is a stepped type, and the number of elements is 16.

As the pressing means 3, 3a, 3b in the configuration as shown in FIG. 1, a TA (Texture Analyzer) was applied.

The main resin composition prepared in Examples and Comparative Examples is filled in any one of the two cartridges (2a, 2b), and after filling the other cartridge with the curing agent composition, a certain force is applied with the pressing means (3, 3a, 3b) After mixing in the static mixer 5 via the first discharging units 4a and 4b, the load value was measured while discharging to the second discharging unit 7 .

That is, the main resin composition and the curing agent composition are injected into the two cartridges (2a, 2b), respectively, and pressurized with a TA (Texture Analyzer) (3a, 3b) at a constant speed of 0.1 mm/s, the static mixer (5) The main resin composition and the curing agent composition are injected into the furnace, and from the time they are first discharged after being mixed in the mixer 5, the force applied to the pressing means is measured, and the maximum value is obtained at the point where the force becomes the maximum value. It was set as the load value (Li). The maximum value is the maximum value initially confirmed in the above process, and is the maximum value at the first point where the applied force is increased and then decreased, or the maximum value at the point where the applied force is increased and then no longer increased.

glass transition temperature

The glass transition temperature was measured using a differential scanning calorimetry (DSC), Mettler. Specifically, after leaving about 10 mg of the curable resin composition prepared in Examples or Comparative Examples at room temperature for 24 hours, using a differential scanning calorimeter at a temperature increase rate of 10° C./min. in the range of -70° C. to 100° C. The glass transition temperature was measured.

Example 1

Main resin: A mixture of 1.4-BD and caprolactone in a ratio of 3:1 (1.4-BD: caprolactone) was used.

Curing agent: HDI uretdione was used.

Inorganic filler: A first alumina filler having an average particle diameter of about 70 μm, a second alumina filler having an average particle diameter of about 20 μm, and a third alumina filler having an average particle diameter of about 2 μm were used. About 89 parts by weight of the inorganic filler based on 100 parts by weight of the curable resin composition was divided and blended in equal amounts with the main resin and the curing agent.

Load reducing agent: a compound represented by the following formula (3), wherein R ₁ and R ₂ are an alkyl group having 4 to 8 carbon atoms substituted with an alkyl group having 2 to 3 carbon atoms, and R ₃ is an alkylene group having 4 to 8 carbon atoms. A reducing agent was used. About 10 parts by weight of the load reducing agent based on 100 parts by weight of the resin component of the curable resin composition was divided and blended in equal amounts to the main resin and the curing agent.

[Formula 3]

Main resin composition: The main resin, inorganic filler and load reducing agent were prepared by mixing with a planetary mixer.

Curable resin composition: The curing agent, the inorganic filler, and the load reducing agent were prepared by mixing with a planetary mixer.

Curable resin composition: The prepared main resin composition and the curing agent composition are mixed with a mixer consisting of a cartridge and a static mixer so that the volume ratio of the main resin included in the main resin composition and the curing agent included in the curing agent composition is 1:1. A curable resin composition was prepared.

Example 2

A main resin composition, a curing agent composition, and a curable resin composition were prepared in the same manner as in Example 1 except that castor oil (CAS: 8001-79-4) was used as the load reducing agent.

Example 3

A main resin composition, a curing agent composition, and a curable resin composition were prepared in the same manner as in Example 2, except that 4,4'-Diphenylmethane diisocyanate was used as the curing agent.

Comparative Example 1

A main resin composition, a curing agent composition, and a curable resin composition were prepared in the same manner as in Example 1, except that Bis(2-ethylhexyl) terephthalate was used as the load reducing agent.

Comparative Example 2

A main resin composition, a curing agent composition, and a curable resin composition were prepared in the same manner as in Example 1 except that epoxidized soy bean oil (harima technology, ESBO 8013-07-8) was used as a load reducing agent.

Comparative Example 3

A main resin composition, a curing agent composition, and a curable resin composition were prepared in the same manner as in Example 1 except that a load reducing agent was not added.

Affinity of load reducing agent for subject resin storage stability load value
(kgf) glass transition temperature
(℃) Example 1 about 0.16 ○ 30 -25 or less Example 2 about 0.5 ○ 29 -25 or less Example 3 about 0.5 ○ 30 15 or less Comparative Example 1 about 0.1 × 33 -25 or less Comparative Example 2 about 0.04 × 36 -25 or less Comparative Example 3 - × 40 35

1: mixer
2, 2a, 2b: cartridge
3, 3a, 3b: pressurizing means
4, 4a, 4b: first discharge unit
5: mixer
6, 6a, 6b: receiving part
7: second discharge unit
10: battery module case
10a: lower plate
10b: side wall
10c: top plate
20: battery cell

Claims (14)

a base resin, a curing agent, an inorganic filler and a load reducing agent;
The main resin is a carboxylic acid polyol or caprolactone polyol,
The curing agent is an isocyanate compound,
The inorganic filler includes a thermally conductive filler having an average particle diameter in the range of 0.001 μm to 100 μm,
The load reducing agent is castor oil, or a compound represented by the following Chemical Formula 3, Chemical Formula 4 or Chemical Formula 5,
A curable resin composition in which A _ij of the following general formula 1 satisfies 0.11 or more:
[General formula 1]
A _ij = min(1, exp(-Δμ _ij /RT))
In the above general formula 1, A _ij is the affinity of the load reducing agent for the main resin, Δμ _ij is the mixing energy of the main resin for the load reducing agent, R is a gas constant, T is the absolute is the temperature:
[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, R ₁ and R ₂ may be the same or different, and each independently represents an alkyl group having 1 to 8 carbon atoms that is unsubstituted or substituted with at least one alkyl group having 1 to 4 carbon atoms, R ₃ , R ₄ and R ₅ may be the same or different, and each independently represents an alkylene group having 1 to 8 carbon atoms that is unsubstituted or substituted with at least one alkyl group having 1 to 4 carbon atoms, and R ₆ and R ₇ may be the same or different, and each An aromatic hydrocarbon independently substituted or unsubstituted with at least one C 1 to C 4 alkyl group. delete The curable resin composition according to claim 1, wherein the carboxylic acid polyol or caprolactone polyol is amorphous or has a melting point (Tm) of less than 15°C. The curable resin composition according to claim 1, wherein the isocyanate compound is a non-aromatic isocyanate compound. According to claim 1, wherein the inorganic filler is aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC) beryllium oxide (BeO), oxide A curable resin composition comprising zinc (ZnO), aluminum hydroxide (Al(OH) ₃ ), boehmite, carbon filler or clay. The curable resin composition of claim 1, wherein the inorganic filler is included in an amount of 70 parts by weight to 95 parts by weight based on 100 parts by weight of the curable resin composition. The curable resin composition according to claim 1, wherein the load reducing agent has a viscosity of 3,000 cP or less measured at 25°C using a Brookfield LV type viscometer. The curable resin composition according to claim 1, wherein the load reducing agent is included in an amount of less than 30 parts by weight based on 100 parts by weight of the resin component of the curable resin composition. The curable resin composition according to claim 1, wherein the curable resin composition has a glass transition temperature (Tg) of 25°C or less. The curable resin composition according to claim 1, wherein the curable resin composition has a load value of less than 40 kgf measured at room temperature immediately after mixing. The method according to claim 1, wherein, when measured in a shear rate range of 0.01 to 10.0/s using a rheometer (ARES) at room temperature within 60 seconds after mixing the curable resin composition, it is measured at a point of 2.5/s A curable resin composition having a viscosity of 250,000 cP to 350,000 cP. a module case having an upper plate, a lower plate, and a side wall, and having an internal space formed by the upper plate, lower plate, and side wall;
a plurality of battery cells existing in the inner space of the module case; and
A battery module comprising a resin layer formed by curing the curable resin composition according to claim 1 and in contact with at least one of the plurality of battery cells and a lower plate or sidewall. A battery pack comprising two or more battery modules of claim 12 that are electrically connected to each other. A vehicle comprising the battery module of claim 12 or the battery pack of claim 13 .

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