Specification
Title of invention: resin composition
Technical field
[One]
Mutual citation with related applications
[2]
This application claims the interest of priority based on Korean Patent Application No. 10-2018-0035749 filed March 28, 2018 and Korean Patent Application No. 10-2019-0029277 filed March 14, 2019. All contents disclosed in the document of the application are included as part of this specification.
[3]
Technical field
[4]
This application relates to a resin composition. Specifically, the present application relates to a resin composition and a battery module including a cured product of the resin composition, a battery pack, and a vehicle.
Background
[5]
The secondary battery includes a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, or a lithium secondary battery, and a representative one is a lithium secondary battery.
[6]
Lithium secondary batteries mainly use lithium oxide and carbon materials as positive and negative active materials, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode active material and a negative electrode active material are applied, respectively, and an electrode assembly in which a negative electrode plate is disposed with a separator interposed therebetween, and a casing material for sealing and receiving the electrode assembly together with an electrolyte. And pouch-type secondary batteries. This single secondary battery may be referred to as a battery cell.
[7]
In the case of a medium or large-sized device such as a vehicle or a power storage device, a battery module in which a large number of battery cells are electrically connected to each other may be used to increase capacity and output, or a battery pack in which a plurality of such battery modules are connected may be used.
[8]
One of the methods of configuring a battery module or a battery pack as described above is to use an adhesive material capable of fixing a plurality of battery cells inside the battery module. In this case, the adhesive material may be injected into the battery module through an injection hole formed on the surface of the battery module.
Detailed description of the invention
Technical challenge
[9]
An object of the present application is to improve the injecting processability of the composition in an adhesive composition that can be used to fix a battery cell in a battery module.
[10]
Another object of the present application is to provide a composition capable of providing excellent insulation, adhesion, heat generation, etc. after being injected into a battery module and cured.
[11]
Another object of the present application is to provide a battery module and a battery pack.
[12]
All of the above and other objects of the present application can be solved by the present application described in detail below.
Means of solving the task
[13]
In an example related to the present application, the present application relates to a curable resin composition used in a battery module or battery pack. Specifically, as described below, the composition of the present application is injected into the case of the battery module, and after curing by contacting at least one battery cell present in the battery module, a composition used to fix the battery cell in the battery module Can be Accordingly, the resin composition may include a main component, and when mixed with the main ingredient may include a curing agent component for curing. In addition, the resin composition may contain a filler as described below.
[14]
With regard to the use of the resin composition, when the curing speed of the resin composition, that is, the adhesive composition is too fast and the viscosity is increased, it is not easy to inject into the module. On the other hand, if the injected liquid adhesive is not sufficiently cured, the viscosity is low. Therefore, if the module is moved or the module is turned over according to the additional process, the adhesive may leak or the parts may be contaminated. Interfaces between the parts that were intended to be bonded may rise. In consideration of these points, the inventors of the present application developed a resin composition that has excellent processability because it has a certain level of curing speed, and that can prevent contamination or peeling between parts that may occur due to adhesives in the battery module manufacturing process. Reached.
[15]
Accordingly, the resin composition of the present application may have curing characteristics of the following speed. In the present application, the curing speed of the resin composition may be expressed as a change in viscosity over time.
[16]
The composition may be a composition that satisfies the initial viscosity change rate defined by the following relational formula 1 within the range of 1.1 to 5.0.
[17]
[Relationship 1]
[18]
Initial viscosity change rate = V 2 /V 1
[19]
In the above relational equation 1, V 1 is the initial viscosity, which is the viscosity value measured at room temperature within 60 seconds after mixing the constituents of the resin composition, that is, the main material and the curing agent, and V 2 is the resin composition in which V 1 is measured at room temperature. It is a viscosity value measured after leaving for 5 minutes. The V 1 and V 2 are viscosity values ​​measured at a point of 2.5/s when measured in a shear rate range of 0.01 to 10.0/s using a rheological property meter (ARES). In the present application, the term "room temperature" is a state that is not particularly heated or reduced in temperature, and any temperature within the range of about 10°C to 30°C, for example, about 15°C or more, about 18°C ​​or more, about 20°C or more, Alternatively, it may mean a temperature of about 23°C or more and about 27°C or less.
[20]
Satisfying the viscosity change rate represented by the relational equation 1 as described above means that the viscosity of the liquid adhesive composition injected at the beginning of the operation for forming the battery module is maintained at a relatively low level. Thereby, a sufficient process load ratio can be ensured.
[21]
In addition, the composition may be a composition that satisfies an initial viscosity change rate of 10 or more, defined by the following relational formula 2.
[22]
[Relationship 2]
[23]
Initial viscosity change rate = V 3 /V 1
[24]
In the above relational formula 2, V 1 is the initial viscosity, which is a viscosity value measured at room temperature within 60 seconds after mixing the constituents of the resin composition, that is, the main and curing agent components, and V 3 is the resin composition in which V 1 is measured at room temperature. It is a viscosity value measured after leaving for 60 minutes. V 1 and V 3 are viscosity values ​​measured at the point of 2.5/s when measured in a shear rate range of 0.01 to 10.0/s using a rheological property meter (ARES).
[25]
Satisfying the viscosity change rate represented by the relational equation 2 as described above means that after 60 minutes elapsed after injection into the battery module, the injected composition can cure to some extent enough to fix the battery cell inside the module case. This means that even if it is moved or flipped over, it can prevent contamination of adjacent parts or lifting between parts interfaces.
[26]
In the present application, the V 1 , V 2 , and V 3 may be referred to as temporary curing viscosity values. In the present application, temporary hardening may mean that the antispasmodic state has not been reached, and the antispasmodic state means that the material injected into the module to manufacture the battery module is cured sufficiently to perform a function as an adhesive with a function such as heat dissipation. It can mean a state that can be viewed as being. Taking a urethane resin as an example, the anti-curing state is based on a 24-hour cure at room temperature and 30 to 70% relative humidity, and the conversion rate of the NCO peak in the vicinity of 2250 cm -1 as confirmed by FT-IR analysis ( conversion) is 80% or more.
[27]
In one example, the value of V 1 of the resin composition may be 500,000 cP or less. Its lower limit may be, for example, 100,000 cP or more. If the range is satisfied, it is advantageous in satisfying the above relations 1 and 2, and accordingly, appropriate fairness can be secured.
[28]
In one example, the value of V 2 of the resin composition may be 2,000,000 cP or less. Satisfying this range means that even though the constituent components of the two-component resin composition described below are mixed and then a curing reaction occurs, adequate flowability is still present in the composition. When the value of V 2 is satisfied, it is advantageous to satisfy the relational expression 1 described above, and appropriate fairness can be secured accordingly.
[29]
In another example, the value of V 3 of the resin composition may be 5,000,000 cP or more. Satisfying the range means that the flowability of the composition is weakened as the curing reaction sufficiently occurs during the normal time expected to be injected into the battery module after the components of the two-component resin composition are mixed. It means that it can be fixed enough. When the V 3 value is satisfied, it is advantageous to satisfy the above-described relational expression 2, and accordingly, appropriate fairness and product durability can be secured.
[30]
Assuming that the above relational expression 1 is satisfied, if necessary, a predetermined measure may be additionally taken to shorten the time at which the viscosity value corresponding to V 3 in the above relational expression 2 is achieved. For example, it is possible to obtain a viscosity value corresponding to V 3 faster by heating or heating the composition at a level that does not adversely affect the components of the battery module .
[31]
The kind of resin composition is not particularly limited as long as it satisfies the curing rate characteristics related to the above-specified viscosity and has adhesiveness suitable for the use after curing.
[32]
In one example, a room temperature curable composition may be used as the resin composition. Room temperature curable composition refers to a composition having a system capable of exerting a predetermined adhesive ability through a curing reaction at room temperature. Alternatively, it may be a two-component acrylic resin composition.
[33]
In one example, the resin composition may provide excellent electrical insulation after curing (semi-curing). When the resin layer exhibits electrical insulation in the battery module structure described below, the performance of the battery module can be maintained and stability can be ensured. For example, after 24 hours after mixing the constituent components of the resin composition, that is, the main material and the curing agent, when measuring the dielectric breakdown voltage of the cured product, the dielectric breakdown voltage is about 10 kV/mm or more, 15 kV/mm or more, or It may be 20 kV/mm or more. The higher the value of the dielectric breakdown voltage is, the higher the value is, the better the resin layer exhibits excellent insulation, so the upper limit is not particularly limited, but considering the composition of the resin layer, about 50 kV/mm or less, 45 kV/mm or less, 40 It may be kV/mm or less, 35 kV/mm or less, or 30 kV/mm or less. The dielectric breakdown voltage can be measured according to ASTM D149, as described in the following Examples. In addition, the dielectric breakdown voltage in the above range may be secured, for example, by adjusting the filler or resin component or the content thereof used in the curable composition described below.
[34]
In one example, the composition may be a two-component urethane-based composition. Two-part urethane refers to a polyurethane formed by mixing an isocyanate-based compound and a polyol-based compound, and is distinguished from a one-component polyurethane having a urethane group in a single composition. When a two-part urethane-based composition is used, the composition may have the following configuration. In the case of the two-component polyurethane, a subject including polyol and a curing agent including an isocyanate may react at room temperature to be cured. The curing reaction may be aided by a catalyst such as dibutyltin dilaurate (DBTDL), for example. Accordingly, the two-part urethane-based composition may include a physical mixture of the main component (polyol) and the curing agent component (isocyanate), and/or may include a reactant (cured product) of the main component and the curing agent component.
[35]
The two-component urethane-based composition may include a main composition part (or main part) including at least a polyol resin, and a curing agent composition part (or a curing agent part) including at least polyisocyanate. Accordingly, the cured product of the resin composition may include both the polyol-derived unit and the polyisocyanate-derived unit. In this case, the polyol-derived unit may be a unit formed by urethane reaction of a polyol with a polyisocyanate, and the polyisocyanate-derived unit may be a unit formed by urethane reaction of a polyisocyanate and a polyol.
[36]
The composition may also contain a filler. For example, in order to secure thixotropy as needed in the process, and/or to secure heat dissipation (thermal conductivity) within a battery module or battery pack, as described below, the composition of the present application contains an excessive amount of filler. Can be included. Specific details will be described in detail in the following related description.
[37]
In one example, an ester-based polyol resin may be used as the polyol resin included in the main composition part. In the case of using an ester-based polyol, it is advantageous in securing excellent adhesion and adhesion reliability in the battery module after curing the resin composition.
[38]
In one example, as the ester-based polyol, for example, a carboxylic acid-based polyol or a caprolactone-based polyol may be used.
[39]
The carboxylic acid-based polyol can be formed by reacting a component including a carboxylic acid and a polyol (ex. diol or triol, etc.), and the caprolactone-based polyol includes caprolactone and a polyol (ex. diol or triol, etc.). It can be formed by reacting components. In this case, the carboxylic acid may be a dicarboxylic acid.
[40]
In one example, the polyol may be a polyol represented by Formula 1 or 2 below.
[41]
[Formula 1]
[42]

[43]
[Formula 2]
[44]

[45]
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.
[46]
In the above formula, the carboxylic acid-derived unit is a unit formed by reacting a carboxylic acid with a polyol, and the polyol-derived unit is a unit formed by reacting a polyol with a carboxylic acid or caprolactone.
[47]
That is, when the hydroxy group of the polyol and the carboxyl group of the carboxylic acid react, the water (HO 2 ) molecule is desorbed by the condensation reaction to form an ester bond, wherein X in Formula 1 is the carboxylic acid to form an ester bond by the condensation reaction. After that, it means the part excluding the ester-linked part. Further, Y is a portion excluding the ester bond after the polyol forms an ester bond by the condensation reaction. The ester bond is represented in Formula 1.
[48]
In addition, Y in Formula 2 also represents a portion excluding the ester bond after the polyol forms an ester bond with caprolactone. The ester bond is represented by Formula 2.
[49]
Meanwhile, in the above formula, when the polyol-derived unit of Y is a unit derived from a polyol containing three or more hydroxy groups, such as a triol unit, a branched structure may be implemented in the Y portion in the above formula.
[50]
In Formula 1, the type of the carboxylic acid-derived unit of X is not particularly limited, but in order to secure the desired physical properties, a phthalic acid unit, an isophthalic acid unit, a terephthalic acid unit, a trimellitic acid unit, a tetrahydrophthalic acid unit, a hexahydrophthalic acid unit, Tetrachlorophthalic acid unit, oxalic acid unit, adipic acid unit, azelaic acid unit, sebacic acid unit, succinic acid unit, malic acid unit, glataric acid unit, malonic acid unit, pimelic acid unit, suberic acid unit, 2,2-dimethyl It may be any one unit selected from the group consisting of succinic acid unit, 3,3-dimethylglutaric acid unit, 2,2-dimethylglutaric acid unit, maleic acid unit, fumaric acid unit, itaconic acid unit, and fatty acid unit. . Considering the low glass transition temperature in the above-described range, an aliphatic carboxylic acid-derived unit may be preferable to an aromatic carboxylic acid-derived unit.
[51]
On the other hand, the kind of the polyol-derived unit of Y in Formulas 1 and 2 is not particularly limited, but in order to secure the desired physical properties, an ethylene glycol unit, a dieltyylene glycol unit, a propylene glycol unit, a 1,2-butylene glycol unit, 2,3-butylene glycol unit, 1,3-propanediol unit, 1,3-butanediol unit, 1,4-butanediol unit, 1,6-hexanediol unit, neopentyl glycol unit, 1,2-ethylhexyl Diol unit, 1,5-pentanediol unit, 1,9-nonanediol unit, 1,10-decanediol unit, 1,3-cyclohexanedimethanol unit, 1,4-cyclohexanedimethanol unit, glycerin unit, and It may be any one or more selected from the group consisting of trimethylolpropane units.
[52]
Meanwhile, in Formula 1, n is an arbitrary number, and the range may be selected in consideration of the desired physical properties of the resin composition or the resin layer, which is a cured product thereof. For example, n may be about 2 to 10 or 2 to 5.
[53]
In addition, in Formula 2, m is an arbitrary number, and the range may be selected in consideration of the desired physical properties of the resin composition or the cured resin layer. For example, m is about 1 to 10 or 1 to 5 days. I can.
[54]
When n and m in Formulas 1 and 2 are out of the above range, crystallinity expression of the polyol increases and may adversely affect the injection processability of the composition.
[55]
The molecular weight of the polyol may be adjusted in consideration of the low viscosity characteristics, durability or adhesiveness described below, and may be, for example, in the range of about 300 to 2,000. Unless otherwise specified, in this specification, the "molecular weight" may be a weight average molecular weight (Mw) measured using GPC (Gel Permeation Chromatograph). If it is out of the above range, the reliability of the resin layer after curing may be poor, or problems related to volatile components may occur.
[56]
In the present application, a polyisocyanate may mean a compound including two or more isocyanate groups.
[57]
In the present application, the type of polyisocyanate included in the curing agent composition portion is not particularly limited, but a non-aromatic isocyanate compound not including an aromatic group may be used to secure desired physical properties. That is, it may be advantageous to use aliphatic or cycloaliphatic series. In the case of using an aromatic polyisocyanate, since the reaction rate may be too fast and the glass transition temperature of the cured product may be increased, it may be difficult to secure fairness and physical properties suitable for use of the composition of the present application.
[58]
For example, aliphatic or alicyclic polyisocyanate or a modified product thereof may be used. Specifically, aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate methyl, ethylene diisocyanate, propylene diisocyanate, or tetramethylene diisocyanate; Aliphatic cyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, bis(isocyanate methyl)cyclohexane diisocyanate or dicyclohexylmethane diisocyanate; Or any one or more of the above carbodiimide-modified polyisocyanate or isocyanurate-modified polyisocyanate; Etc. can be used. In addition, a mixture of two or more of the compounds listed above may be used.
[59]
The ratio of the polyol-derived resin component and the polyisocyanate-derived resin component in the resin composition is not particularly limited, and may be appropriately adjusted to enable a urethane reaction therebetween.
[60]
As described above, in order to secure heat dissipation (thermal conductivity) or to secure thixotropy according to process needs, an excessive amount of filler may be included in the composition. When an excessive amount of filler is used, the viscosity of the composition increases and the battery module Fairness when injecting the composition into the case of may deteriorate. Therefore, there is a need for sufficient low viscosity properties to include an excess of filler and not interfere with fairness. In addition, if only a low viscosity is shown, it is also difficult to secure fairness, so appropriate thixotropy is required, and during curing, it may be necessary to exhibit excellent adhesion, and the curing itself may need to proceed at room temperature. In addition, ester-based polyols are advantageous in securing adhesion after curing, but because they have strong crystallinity, they are highly likely to become waxy at room temperature, and there is a disadvantage in securing proper injection processability due to an increase in viscosity. Even if the viscosity is lowered through melting, due to the crystallinity that occurs naturally in the storage process, viscosity increase due to crystallization in the injection or application process of the composition that can be followed after mixing with the filler occurs. And, as a result, fairness may deteriorate. In consideration of this point, the ester-based polyol used in the present application may satisfy the following characteristics.
[61]
In the present application, the ester-based polyol may be amorphous or a polyol having sufficiently low crystallinity. In the above, "amorphous" means a case where the crystallization temperature (Tc) and melting temperature (Tm) are not observed in DSC (Differential Scanning calorimetry) analysis. The DSC analysis can be performed using a known apparatus, for example, Q2000 (TA Instruments Co., Ltd.). Specifically, the DSC analysis can be performed within the range of -80 to 60°C at a rate of 10°C/min (min), for example, after raising the temperature from 25°C to 50°C at the rate -70°C The temperature may be reduced, and the temperature may be raised to 50°C again. In addition, "sufficiently low crystallinity" means that the melting point or melting temperature (Tm) observed in DSC analysis is less than 15°C, about 10°C or less, 5°C or less, 0°C or less, -5°C or less, -It means less than 10℃, or-less than 20℃. 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 higher, about -75°C or higher, or about -70°C or higher. When the polyol is crystallinity or does not satisfy the melting point range (at room temperature) when crystallinity is strong, the viscosity difference according to temperature tends to be large, so the dispersion of the filler and the viscosity of the final mixture in the process of mixing the filler and the resin It may adversely affect the process, deteriorate processability, and as a result, it may be difficult to satisfy the cold resistance, heat resistance, and water resistance required in the adhesive composition for a battery module.
[62]
1 is an example of determining the amorphous or sufficiently low crystallinity of the ester-based polyol, and is a graph showing DSC analysis results for several polyols. According to the present application, Sample #1 may be determined to be amorphous, and Sample #2 and #3 may be determined to have sufficiently low crystallinity. On the other hand, in the case of sample #4 with a melting temperature (Tm) of 33.52 ℃, it can be said that the crystallinity is high.
[63]
In one example, the polyol resin and the isocyanate component included in the urethane-based composition may have a glass transition temperature (Tg) of less than 0°C after curing (evaporation).
[64]
When the glass transition temperature range is satisfied, brittle characteristics can be secured within a relatively short time even at a low temperature at which the battery module or battery pack can be used, thereby ensuring impact resistance or vibration resistance. I can. On the other hand, if the above range is not satisfied, there is a possibility that tacky of the cured product is too high or thermal stability is deteriorated. In one example, the lower limit of the glass transition temperature of the urethane-based composition after curing may be -70°C or higher, -60°C or higher, -50°C or higher, -40°C or higher, or -30°C or higher, and the upper limit is -5 ℃ or less, -10 ℃ or less, -15 ℃ or less, or may be -20 ℃ or less. The glass transition temperature may be measured after curing the polyol resin and the isocyanate component (without filler).
[65]
In addition, in the present application, additives may be used to secure the use of the resin composition and functions required according to the use. For example, the resin composition may include a predetermined filler in consideration of thermal conductivity, insulation, and heat resistance (TGA analysis) of the resin layer. The form or method in which the filler is included in the resin composition is not particularly limited. For example, the filler may be used to form a urethane-based composition in a state previously included in the main composition part and/or the curing agent composition part. Alternatively, in the process of mixing the main composition part and the curing agent composition part, it may be used in a manner in which a separately prepared filler is mixed together.
[66]
In one example, at least, the filler included in the composition may be a thermally conductive filler. In the present application, the term thermally conductive filler may mean 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. Specifically, 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 type of the thermally conductive filler that can be used is not particularly limited, but may be a ceramic filler when insulating properties are considered together. For example, ceramic particles such as alumina, aluminum nitride (AlN), boron nitride (BN), silicon nitride, SiC or BeO may be used. The shape or ratio of the filler is not particularly limited, and is appropriately adjusted in consideration of the viscosity of the urethane-based composition, the possibility of sedimentation in the cured resin layer, the desired heat resistance or thermal conductivity, insulation, filling effect, or dispersibility. Can be. In general, as the size of the filler increases, the viscosity of the composition containing the filler increases, and the likelihood that the filler precipitates in the resin layer increases. In addition, as the size decreases, the thermal resistance tends to increase. Therefore, in consideration of the above points, a filler of an appropriate type and size may be selected, and if necessary, two or more 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 a form such as a needle or plate may be used in consideration of network formation or conductivity. The thermal conductivity of the filler can be measured according to a known method, in which case,
[67]
In one example, the composition may include a thermally conductive filler having an average particle diameter in the range of 0.001 μm to 80 μm. In another example, the average particle diameter of the filler may be 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 other examples, the average particle diameter of the filler is about 75 μm or less, about 70 μm or less, about 65 μm or less, about 60 μm or less, about 55 μm or less, about 50 μm or less, about 45 μm or less, about 40 μm or less, about It may be 35 μm or less, about 30 μm or less, about 25 μm or less, about 20 μm or less, about 15 μm or less, about 10 μm or less, or about 5 μm or less. The average particle diameter may be measured using a particle size analysis (PSA) equipment. In one example, the average particle size may mean D(50), which is the 50th-ranked particle size when ranking particles from 1 to 100 for each size.
[68]
In order to obtain excellent heat dissipation performance, it may be considered that a thermally conductive filler is used in a high content. For example, the filler may be used within a range of about 50 to 2,000 parts by weight, based on 100 parts by weight of the total resin component, that is, the total amount of the ester-based polyol resin and polyisocyanate. In another example, the content of the filler may be used in excess of the total resin component. Specifically, based on 100 parts by weight of the total amount of the ester-based polyol resin and polyisocyanate, about 100 parts by weight or more, about 150 parts by weight or more, about 200 parts by weight or more, about 250 parts by weight or more, about 300 parts by weight or more, About 350 parts by weight or more, about 400 parts by weight or more, about 500 parts by weight or more, about 550 parts by weight or more, about 600 parts by weight or more, or about 650 parts by weight or more of a filler may be used. In one example, when the filler is used in the above range, it may be distributed in the same amount to the main composition part and the hardener composition part.
[69]
As described above, when the thermally conductive filler is used in a high content, the viscosity of the main composition part including the filler, the curing agent composition part, or the composition including the same may increase. As described, if the viscosity of the resin composition is too high, the injection processability is not good, and accordingly, physical properties required for the resin layer may not be sufficiently implemented in the entire resin layer. In consideration of this point, it is preferable to use a liquid or low viscosity component capable of having sufficient flow as the resin component.
[70]
In one example, each of the ester-based polyol resin and the polyisocyanate component may have a viscosity of 10,000 cP or less. Specifically, the resin component may have a viscosity of 8,000 cP or less, 6,000 cP or less, 4,000 cP or less, 2,000 cP, or 1,000 CP or less. Preferably, the upper limit of the viscosity may be 900 cP or less, 800 cP or less, 700 cP or less, 600 cP or less, 500 cP or less, or 400 cP or less. Although not particularly limited, the lower limit of the viscosity of each resin component may be 50 cP or more or 100 cP or more. If the viscosity is too low, fairness may be good, but as the molecular weight of the raw material decreases, the possibility of volatilization increases, and heat resistance/cold resistance, flame retardance, and adhesion may deteriorate, and this disadvantage can be prevented by satisfying the lower limit range. The viscosity of the resin can be measured at room temperature using, for example, a Brookfield LV type viscometer.
[71]
In addition to the above, various types of fillers may be used. For example, in order to secure the insulating properties of the resin layer cured with the resin composition, use of a carbon (based) filler such as graphite may be considered. Alternatively, for example, a filler such as fumed silica, clay or calcium carbonate may be used. The form or content ratio of the filler is not particularly limited, and may be selected in consideration of the viscosity of the resin composition, the possibility of sedimentation in the resin layer, thixotropy, insulation, filling effect, or dispersibility.
[72]
The composition may contain a viscosity modifier such as a thixotropic agent, a diluent, a dispersant, a surface treatment agent or a coupling agent, etc. May contain additional.
[73]
The thixotropy imparting agent may control the viscosity according to the shear force of the resin composition so that the manufacturing process of the battery module is effectively performed. As the thixotropic imparting agent that can be used, fumed silica and the like can be exemplified.
[74]
Diluents or dispersants are usually used to lower the viscosity of the resin composition, and any of various types known in the art may be used without limitation as long as it can exhibit the above-described action.
[75]
The surface treatment agent is for surface treatment of the filler introduced into the resin layer, and various types known in the art may be used without limitation as long as it can exhibit the above-described action.
[76]
In the case of the coupling agent, for example, it may be used to improve the dispersibility of a thermally conductive filler such as alumina, and any of various types known in the art may be used without limitation as long as it can exhibit the above-described action.
[77]
In addition, the resin composition may further include a flame retardant or a flame retardant auxiliary. In this case, a known flame retardant may be used without particular limitation, and for example, a solid filler type flame retardant or a liquid flame retardant may be applied. Examples of the flame retardant include organic flame retardants such as melamine cyanurate and inorganic flame retardants such as magnesium hydroxide. If the amount of filler to be filled in the resin layer is large, a liquid-type flame retardant material (TEP, Triethyl phosphate or TCPP, tris(1,3-chloro-2-propyl)phosphate, etc.) may be used. In addition, a silane coupling agent capable of acting as a flame retardant enhancing agent may be added.
[78]
The composition may include the configuration as described above, and may be a solvent-type composition, an aqueous composition, or a solvent-free composition, but in consideration of convenience of the manufacturing process described below, a solvent-free type may be appropriate.
[79]
The composition of the present application may have physical properties suitable for use as described below after curing. Among the physical properties mentioned in the present specification, when the measured temperature affects the physical properties, the physical properties may be those measured at room temperature unless otherwise stated. In addition, in relation to physical properties, the expression "after curing" may have the same meaning as the above-described curing.
[80]
In one example, the resin composition has a predetermined adhesive strength at room temperature after curing (S 1). Specifically, the resin layer may have an adhesive strength of about 150 gf/10mm or more, 200 gf/10mm or more, 250 gf/10mm or more, 300 gf/10mm or more, 350 gf/10mm or more, or 400 gf/10mm or more. When the adhesive force satisfies the above range, appropriate impact resistance and vibration resistance can be secured. The upper limit of the adhesive force of the resin layer is not particularly limited, and for example, about 1,000 gf/10mm or less, 900 gf/10mm or less, 800 gf/10mm or less, 700 gf/10mm or less, 600 gf/10mm or less, or 500 gf/ It may be about 10 mm or less. If the adhesion is too high, there is a risk that the cured composition and the portion of the pouch to which it adheres are torn. Specifically, in the event of an impact such as to change the shape of the battery module due to an accident while driving a car, if the battery cell is attached too strongly through the cured resin layer, the pouch is torn and the dangerous substances inside the battery are exposed or exploded. can do. The adhesion can be measured for an aluminum pouch. For example, an aluminum pouch used for manufacturing a battery cell is cut to a width of about 10 mm, a resin composition is loaded on a glass plate, and the cut aluminum pouch is placed on the pouch's PET (poly(ethylene terephthalate)). ) After loading so that the surface and the resin composition are in contact, the resin composition is cured at 25° C. and 50% RH for 24 hours, and the aluminum pouch is subjected to a peel angle of 180° and 300 mm/min with a tensile tester (Texture analyzer). The adhesion can be measured while peeling at a peeling rate of.
[81]
In another example, the adhesive strength after curing of the resin composition may be maintained at a considerable level even under high temperature/high humidity. Specifically, in the present application, with respect to the adhesive force (S 1 ) after curing measured at room temperature, the % of the adhesive force (S 2 ) measured by the same method after performing a high temperature/high humidity acceleration test performed under a predetermined condition The ratio [(S 2 /S 1 ) x 100] may be 70% or more, or 80% or more. In one example, the high temperature/high humidity acceleration test may be measured after storing the same specimen as the specimen used to measure the room temperature adhesion for 10 days at a temperature of 40 to 100° C. and a humidity condition of 75% RH or more. When the above adhesion and relationship are satisfied, excellent adhesion durability can be maintained even when the use environment of the battery module changes.
[82]
In one example, the resin composition may have excellent heat resistance after curing. In this regard, when the composition of the present application does not contain a filler, when thermogravimetric analysis (TGA) is measured for a cured product of only the resin component, the temperature of 5% weight loss is 120°C. It can be more than that. In addition, when the composition of the present application includes a filler, when thermogravimetric analysis (TGA) is measured for the cured product of the resin composition, the remaining amount at 800° C. may be 70% by weight or more. In another example, the residual amount of 800° C. may be about 75% by weight or more, about 80% by weight or more, about 85% by weight or more, or about 90% by weight or more. In another example, the residual amount of 800° C. may be about 99% by weight or less. At this time, thermogravimetric analysis (TGA) may be measured in a range of 25 to 800°C at a temperature increase rate of 20°C/min in a nitrogen (N 2 ) atmosphere of 60 cm 3 /min . Heat resistance properties related to the thermogravimetric analysis (TGA) can be secured by controlling the type or content of resins and/or fillers.
[83]
In another example related to the present application, the present application relates to a battery module. The module includes a module case and a battery cell. The battery cell may be housed in the module case. One or more battery cells may exist 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. Battery cells accommodated in the module case may be electrically connected to each other.
[84]
The module case may include at least a sidewall and a lower plate forming an inner space in which the battery cells can be accommodated. In addition, the module case may further include an upper plate sealing the inner space. The sidewall, the lower plate, and the upper plate may be integrally formed with each other, or the module case may be formed by assembling separate sidewalls, lower plates and/or upper plates respectively. The shape and size of the module case is not particularly limited, and may be appropriately selected according to the purpose or the shape and number of battery cells accommodated in the internal space.
[85]
In the above, the terms upper plate and lower plate are terms of a relative concept used to distinguish them because there are at least two plates constituting the module case. In other words, it does not mean that the upper plate must be present on the upper side and the lower plate must be present on the lower side in the actual use state.
[86]
FIG. 2 is a view showing an exemplary module case 10, and is an example of a case 10 in the form of a box including one lower plate 10a and four side walls 10b. The module case 10 may further include an upper plate 10c sealing the inner space.
[87]
3 is a schematic view of the module case 10 of FIG. 2 in which the battery cells 20 are accommodated, as viewed from above.
[88]
Holes may be formed in the lower plate, sidewall and/or upper plate of the module case. As will be described later, the hole may be an injection hole used to inject a material for forming the resin layer, that is, a resin composition when a resin layer is formed by an injection process. The shape, number, and position of the holes may be adjusted in consideration of the 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.
[89]
In one example, the hole may be formed at about 1/4 to 3/4 point, about 3/8 to 7/8 point, or about the middle part of the total length of the side wall, the lower plate, or the upper plate. By injecting the resin composition through the injection hole formed at this point, it can be injected so that the resin layer has a wide contact surface. The 1/4, 3/4, 3/8, or 7/8 points are, for example, as shown in FIG. 4, the total length (L ), it is the ratio of the distance (A) to the formation position of the hole. In addition, the end (E) where the length (L) and the distance (A) are formed may be any end (E) as long as the length (L) and the distance (A) are measured from the same end (E). have. In FIG. 4, the injection hole 50a is located in an approximately middle portion of the lower plate 10a.
[90]
The size and shape of the injection hole are not particularly limited, and may be adjusted in consideration of the injection efficiency of the resin layer material to be described later. For example, the hole may be polygonal or amorphous, such as a circle, an oval, a triangle, or a square. The number of injection holes and their spacing are not particularly limited, and as described above, the resin layer may be adjusted to have a large contact area with the lower plate.
[91]
Observation holes (eg, (50b) in FIG. 4) may be formed at ends of the upper plate and the lower plate in which the injection holes are formed. The observation 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, for example, when the resin layer material is injected through the injection hole. The position, shape, size, and number of the observation holes are not particularly limited as long as they are formed to confirm whether the injected material is properly injected.
[92]
The module case may be a thermally conductive case. The term thermally conductive case means a case including a portion having a thermal conductivity of 10 W/mk or more, or at least as described above. For example, at least one of the above-described sidewall, lower plate, and upper plate may have the thermal conductivity described above. In another example, at least one of the sidewall, 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 filler-containing cured resin layer in contact with the upper plate and the battery cell, and a second filler-containing cured resin layer in contact with the lower plate and the battery cell, as described later. However, at least the second filler-containing cured resin layer may be a thermally conductive resin layer, and accordingly, at least the lower plate may have thermal conductivity or may include a thermally conductive portion.
[93]
In the above, the thermal conductivity of the upper plate, lower plate, sidewall, or thermally conductive portion, which is thermally conductive, is 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 195 W/mk or more. The higher the thermal conductivity, the higher the value is, the more advantageous it is in terms of heat dissipation characteristics of the module, and thus 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, It may be 300 W/mk or 250 W/mK or less, but is not limited thereto. The type of material exhibiting the above thermal conductivity is not particularly limited, and examples include metal materials such as aluminum, gold, pure silver, tungsten, copper, nickel or platinum. 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 include at least one portion having a thermal conductivity in the above-mentioned range or a portion having the above-mentioned thermal conductivity.
[94]
In the module case, the portion having the thermal conductivity in the above range may be a portion in contact with the resin layer and/or the insulating layer to be described later. 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 discharged to the outside.
[95]
The type of battery cells accommodated in the module case is also not particularly limited, and various known battery cells may be applied. In one example, the battery cell may be a pouch type. Referring to FIG. 5, the pouch-type battery cell 100 may typically include an electrode assembly, an electrolyte, and a pouch case.
[96]
5 is an exploded perspective view schematically showing the configuration of an exemplary pouch-type cell, and FIG. 6 is a combined perspective view of the configuration of FIG. 5.
[97]
The electrode assembly 110 included in the pouch-shaped cell 100 may have a form in which one or more positive plates and one or more negative plates are disposed with a separator therebetween. The electrode assembly 110 may be a winding type in which one positive plate and one negative plate are wound together with a separator, or a stack type in which a plurality of positive plates and a plurality of negative plates are alternately stacked with a separator interposed therebetween.
[98]
The pouch exterior material 120 may be configured in a form including, for example, an outer insulating layer, a metal layer, and an inner adhesive layer. These exterior materials 120 protect internal elements such as the electrode assembly 110 and the electrolyte, and include a thin metal film such as aluminum in consideration of supplementation and heat dissipation properties of the electrode assembly 110 and the electrolyte. I can. The metal thin film may be interposed between an insulating layer formed of an insulating material in order to secure electrical insulation from elements such as the electrode assembly 110 and an electrolyte or other elements outside the battery 100. In addition, the pouch may further include a polymer resin layer (substrate) such as PET.
[99]
In one example, the exterior material 120 may include an upper pouch 121 and a lower pouch 122, and at least one of the upper pouch 121 and the lower pouch 122 has a concave inner space (I) Can be formed. The electrode assembly 110 may be accommodated in the inner space I of the pouch. A sealing part S is provided on the outer circumferential surfaces of the upper pouch 121 and the lower pouch 122, and the sealing parts S are adhered to each other, so that the inner space in which the electrode assembly 110 is accommodated may be sealed.
[100]
Each electrode plate of the electrode assembly 110 is provided with an electrode tab, and one or more electrode tabs may be connected to the electrode lead. The electrode lead is interposed between the sealing portion S of the upper pouch 121 and the lower pouch 122 and exposed to the outside of the exterior material 120, thereby functioning as an electrode terminal of the secondary battery 100.
[101]
The shape of the pouch-type cell described above is only an example, and the battery cell applied in the present application is not limited to the above type. In the present application, known various types of pouch-type cells or other types of batteries may all be applied as battery cells.
[102]
The battery module of the present application may further include a resin layer. Specifically, the battery module of the present application may include a cured resin layer in which the filler-containing composition is cured. The cured resin layer may be formed from the urethane-based composition described above.
[103]
The battery module may include, as the resin layer, a first filler-containing cured resin layer in contact with the upper plate and battery cells, and a second filler-containing cured resin layer in contact with the lower plate and battery cells. At least one of the first and second filler-containing cured resin layers may include the cured product of the urethane-based composition described above, and thus may have a predetermined adhesion, cold resistance, heat resistance, and insulation as described above. In addition, the first and second filler-containing cured resin layers may have the following characteristics.
[104]
In one example, the resin layer may be a thermally conductive resin layer. In this case, the thermal conductivity of the thermally conductive resin layer may be about 1.5 W/mK or more, about 2 W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more, or 4 W/mK or more. . The thermal conductivity is 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 Hereinafter, it may be 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 portion having a 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 measured using a known hot disk device, and is a value measured according to, for example, 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 contained in the resin layer and the content ratio thereof as described above.
[105]
In one example, the heat resistance of the resin layer or the battery module to which the resin layer is applied in the battery module is 5 K/W or less, 4.5 K/W or less, 4 K/W or less, 3.5 K/W or less, 3 K /W or less or about 2.8 K/W or less. When the resin layer or the battery module to which the resin layer is applied is controlled so that the thermal resistance within the above range is displayed, excellent cooling efficiency or heat dissipation efficiency can be ensured. The measurement of the thermal resistance may be calculated based on the temperature measured from the sensor by attaching a temperature sensor according to the cell position on the module while driving the battery module. The method of measuring the heat resistance is not particularly limited, and for example, the heat resistance may be measured according to ASTM D5470 standard or ISO 22007-2 standard.
[106]
In one example, the resin layer may be a resin layer formed to maintain durability even in a predetermined thermal shock test. The thermal shock test can be carried out in a manner known in the art. For example, when holding for 30 minutes at a low temperature of about -40°C and then raising the temperature to 80°C for 30 minutes as one cycle, the module case of the battery module or the battery module after the thermal shock test repeated 100 times It may be a resin layer that may not be peeled off or cracked from the battery cell. For example, when the battery module is applied to a product that requires a long warranty period (about 15 years or more in the case of a vehicle), such as a vehicle, the above-described level of performance may be required to secure durability.
[107]
In one example, 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 exhibiting a V-0 rating in UL 94 V Test (Vertical Burning Test). Through this, it is possible to secure stability against fire and other accidents that may occur in the battery module.
[108]
In one example, the resin layer may have a specific gravity of 5 or less. In another example, the specific gravity may be 4.5 or less, 4 or less, 3.5 or less, or 3 or less. A resin layer exhibiting a specific gravity in this range is advantageous for manufacturing a more lightweight battery module. As the specific gravity is lower, the lower the value is, the more advantageous it is to reduce the weight of the module, so the lower limit thereof is not particularly limited. For example, the specific gravity may be about 1.5 or more or 2 or more. Components added to the resin layer may be adjusted in order for the resin layer to exhibit specific gravity in the above range. For example, when the filler is added, a filler capable of securing a desired thermal conductivity even at as low a specific gravity as possible, that is, a filler having a low specific gravity by itself, or a filler having a surface treatment may be used.
[109]
In one example, it is preferable that the resin layer does not contain volatile substances. For example, the resin layer may have a nonvolatile content of 90% by weight or more, 95% by weight or more, or 98% by weight or more. In the above, the non-volatile components and their ratio can be defined in the following manner. That is, the portion remaining after the resin layer is held at 100° C. for about 1 hour can be defined as a nonvolatile component. Therefore, the ratio of the non-volatile component can be measured based on the initial weight of the resin layer and the ratio after being maintained at 100° C. for about 1 hour.
[110]
In one example, it may be advantageous for the resin layer to have a low shrinkage during the curing process or after curing. Through this, it is possible to prevent the occurrence of delamination or voids that may occur during the manufacturing or use of the module. The shrinkage rate may be appropriately adjusted within a range capable of exhibiting the above-described effect, and may be, for example, less than 5%, less than 3%, or less than about 1%. Since the shrinkage ratio is more advantageous as the value is lower, the lower limit thereof is not particularly limited.
[111]
In one example, the resin layer may have a low coefficient of thermal expansion (CTE) in order to prevent peeling or voids that may occur during the manufacturing or use of the module. The coefficient of thermal expansion may be, for example, less than 300 ppm/K, less than 250 ppm/K, less than 200 ppm/K, less than 150 ppm/K, or less than about 100 ppm/K. The lower the value of the coefficient of thermal expansion is, the more advantageous it is, the lower limit thereof is not particularly limited. The method of measuring the coefficient of thermal expansion is not particularly limited. For example, by using TMA (Thermo Mechanical Analyze) in expansion mode, under 0.05N load, measuring at -40 to 125 degrees and 5 ℃/min conditions, check the length strain within the specified temperature range based on the strained length. The coefficient of thermal expansion can be measured in such a way.
[112]
In one example, in order to impart excellent durability or impact resistance to the battery module, the resin layer may have an appropriate level of tensile strength. For example, the resin layer may be configured to have a Young's modulus of about 1.0 MPa or more. Young's modulus is measured in tensile mode at low temperature (about -40°C), room temperature (about 25°C), and high temperature (about 80°C) for each point within the range of -40 to 80°C, for example. It may be a slope value in the case of Young's modulus is measured lower as the temperature increases. For example, the resin layer of the present application may have a Young's modulus of 1.0 Mpa or more, more specifically, in the range of 10 to 500 Mpa within the section. When the Young's Modulus is less than the above range, the function of fixing a cell having a large weight is not good, and when the Young's Modulus is too large, since the brittle characteristic is strong, cracks may occur in an impact situation such as a vehicle collision.
[113]
In one example, it may be advantageous for the resin layer to exhibit an appropriate hardness. For example, if the hardness of the resin layer is too high, since the resin layer has brittle characteristics, reliability may be adversely affected. In consideration of these points, impact resistance and vibration resistance can be secured and durability of the product can be secured by adjusting the hardness of the resin layer. The resin layer, for example, has a hardness of less than 100, 99 or less, 98 or less, 95 or less, or 93 or less in Shore A type, or has a hardness of less than about 80, about 70 or less, or about 70 or less in Shore D type. It may be 65 or less or about 60 or less. The lower limit of the hardness is not particularly limited. For example, the hardness may be about 60 or more in the shore A type, or about 5 or more or about 10 or more in the shore 00 type. The hardness in the above range can be secured by adjusting the content of the filler. Shore hardness can be measured according to a known method using a hardness tester suitable for each type, such as a shore A hardness tester. Known methods include ASTM D2240 and the like.
[114]
By forming a cured resin layer that satisfies the above characteristics in the battery module as described above, a battery module having excellent durability against external shock or vibration can be provided.
[115]
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 thermally conductive sidewall, the lower plate, or the upper plate. Meanwhile, in the present specification, the term contact means, for example, the resin layer and the upper plate, the lower plate and/or the sidewall or the battery cell are in direct contact, or other elements, such as an insulating layer, are present therebetween. It can also mean a case. 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. In this case, in the thermal contact, the resin layer is in direct contact with the lower plate or the like, or another element such as an insulating layer to be described later exists between the resin layer and the lower plate. 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 obstructed. In the above, that it does not interfere with the transfer of heat means that even when another element (ex. an insulating layer or a guiding part to be described later) 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, about 2 W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more, or 4 W/mK or more, or is in contact with the resin layer and This means that the total thermal conductivity of the lower plate, etc., is within the above range even when the other elements are present. The thermal conductivity of the thermal contact is 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, It may be 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 can be achieved by controlling the thermal conductivity and/or thickness of the other element, if present.
[116]
The thermally conductive resin layer may be in thermal contact with the lower plate or the like, and may also be in thermal contact with the battery cell. Through the adoption of the structure as described above, it secures heat dissipation characteristics while significantly reducing various fastening parts or cooling equipment of modules that were previously required when configuring a general battery module or a battery pack that is an assembly of such modules. It is possible to implement a module in which more battery cells are accommodated per unit. Accordingly, in the present application, a smaller, lighter, and high-output battery module can be provided.
[117]
7 is an exemplary cross-sectional view of the battery module. In FIG. 6, the module includes: a case 10 including a side wall 10b and a lower plate 10a; It may have a shape including a plurality of battery cells 20 accommodated in the case and a resin layer 30 in contact with both the battery cells 20 and the case 10. 7 is a view of the resin layer 30 present on the lower plate 10a side, but the battery module of the present application may include a resin layer positioned on the upper plate side in the same shape as in FIG. 7.
[118]
In the above structure, the lower plate or the like in contact with the resin layer 30 may be a lower plate having thermal conductivity, as described above.
[119]
The contact area between the resin layer and the lower plate may be about 70% or more, about 75% or more, about 80% or more, about 85% or more, about 90% or more, or about 95% or more of the total area of ​​the lower plate. The upper limit of the contact area is not particularly limited, and may be, for example, 100% or less or about 100% or less.
[120]
When the upper plate or the lower plate is thermally conductive, and the cured resin layer in contact therewith is also thermally conductive, the thermally conductive portion or the thermally conductive lower plate may be a portion in contact with a cooling medium such as cooling water. That is, as schematically shown in FIG. 7, heat (H) can be easily discharged to the lower plate by the above structure, and by contacting the lower plate with the cooling medium (CW), even in a more simplified structure You can make it easier to dissipate heat.
[121]
Each of the first and second cured resin layers may have a thickness in a range of, for example, about 100 μm to 5 mm or about 200 μm to 5 mm. In the structure of the present application, the thickness of the resin layer may be set to an appropriate thickness in consideration of desired heat dissipation properties or durability. The thickness may be the thickness of the thinnest portion of the resin layer, the thickness of the thickest portion, or an average thickness.
[122]
As shown in FIG. 7, at least one surface inside the module case 10, for example, on a surface 10a in contact with the resin layer 30, a guiding unit capable of guiding the battery cell 20 accommodated ( 10d) may exist. At this time, the shape of the guiding part 10d is not particularly limited, and an appropriate shape may be employed in consideration of the shape of the applied battery cell. The guiding part 10d may be integrally formed with the lower plate or the like, or may be separately attached. The guiding part 10d may be formed of a thermally conductive material, for example, a metal material such as aluminum, gold, pure silver, tungsten, copper, nickel, or platinum in consideration of the aforementioned thermal contact. In addition, although not shown in the drawings, an interlayer paper or an adhesive layer may be present between the battery cells 20 to be accommodated. In the above, the separator may serve as a buffer during charging and discharging of the battery cell.
[123]
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. FIG. 8 exemplarily shows a case in which the insulating layer 40 is formed between the guiding portion 10d formed on the lower plate 10a of the case and the resin layer 30. By adding an insulating layer, it is possible to prevent problems such as electric short-circuit phenomenon or fire occurrence due to contact between the cell and the case due to 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 injection of an insulating material. For example, in a method of manufacturing a battery module to be described later, a process of forming an insulating layer before injection of the resin composition may be performed. A so-called TIM (Thermal Interface Material) or the like may be applied to the formation of the insulating layer. In another way, the insulating layer may be formed of an adhesive material, and for example, the insulating layer may be formed using a resin layer having a low or no filler content such as a thermally conductive filler. Resin components that can be used to form the insulating layer include acrylic resin, olefin resin such as PVC (poly(vinyl chloride)), PE (polyethylene), epoxy resin, silicone, or EPDM rubber ((ethylene propylene diene monomer rubber). Rubber components, etc. may be exemplified, but are not limited thereto. The insulation layer has an insulation breakdown voltage of about 5 kV/mm or more, about 10 kV/mm or more, and about 15 kV as measured in accordance with ASTM D149. /mm or more, 20 kV/mm or more, It may be 25 kV/mm or more or 30 kV/mm or more. The dielectric breakdown voltage is not particularly limited as it exhibits excellent insulation as the value increases. For example, the dielectric breakdown voltage of the insulating 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 60 kV/mm or less. The thickness of the insulating layer can be set in an appropriate range in consideration of the insulating properties or thermal conductivity of the insulating layer, for example, about 5 μm or more, about 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, 80 μm or more, or 90 μm or more. In addition, the upper limit of the thickness is not particularly limited, and may be, for example, about 1 mm or less, about 200 μm or less, 190 μm or less, 180 μm or less, 170 μm or less, 160 μm or less, or 150 μm or less.
[124]
In another example related to the present application, the present application relates to a battery module, for example, a method of manufacturing the aforementioned battery module.
[125]
The manufacturing method of the present application includes the steps of injecting the resin composition into the module case; It may include accommodating a battery cell in the module case and forming the resin layer by curing the resin composition.
[126]
The order of the step of injecting the resin composition into the module case and the step of accommodating the battery cell in the module case is not particularly limited. For example, the resin composition may be first injected into the module case, and then the battery cell may be stored in that state, or the resin composition may be injected after the battery cell is first stored inside the module case.
[127]
As the resin composition, the resin composition described above can be used.
[128]
The method of injecting the resin composition into the module case is not particularly limited, and a known method may be applied. For example, a resin composition is poured into the opening of the module case to inject the resin composition, or the resin composition is injected through the above-described injection hole formed in the module case, and the resin composition is applied to both the battery cell and the battery module. A method of applying, etc. may be applied. For proper fixation, the injection process may be performed while constantly vibrating the battery module or battery cell.
[129]
The method of accommodating the battery cells in the module case into which the resin composition is injected or the module case before the composition is injected is not particularly limited.
[130]
The storage of the battery cells can be performed by placing the battery cells in an appropriate position in the module case in consideration of a desired arrangement or the like. In addition, when the cartridge structure is present, the above step may be performed by placing the battery cell in an appropriate position of the cartridge structure or inserting the cartridge structure in which the battery cell is located into the module case.
[131]
After accommodating the battery cells, adhesion between the battery cells or adhesion between the battery cells and the module case may be formed by curing the injected resin composition. The method of curing the resin composition is not particularly limited. In one example, when the composition is used, the resin composition may be cured by maintaining the resin composition for a predetermined time (about 24 hours) at room temperature. At a level that does not impair the thermal stability of the cell, it is also possible to accelerate curing by applying heat for a certain period of time. For example, before curing or in the curing process or in the storage or storage process of the battery cell, by applying heat in the range of less than 60°C, more specifically in the range of about 30°C to 50°C, reducing the tack time And improve fairness. A cured product capable of bonding between battery cells or bonding between battery cells and module case may have a conversion rate of at least 80% or more, as described above.
[132]
In another example of the present application, the present application 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 all known methods may be applied.
[133]
The present application also relates to the battery module or to a device comprising the battery pack. An example of the device may be a vehicle such as an electric vehicle, but is not limited thereto, and may be a device for any purpose requiring a secondary battery as an output. In addition, a method of configuring the vehicle using the battery module or battery pack is not particularly limited, and a general method known in the related art may be applied.
Effects of the Invention
[134]
According to an example of the present application, there is provided a resin composition that has excellent injection processability into a battery module and can prevent contamination of other components in the battery module after injection. In addition, the composition has excellent insulation, heat dissipation, and adhesion after curing.
Brief description of the drawing
[135]
1 shows an example of determining the amorphous property or sufficiently low crystallinity of an ester-based polyol according to an example of the present application.
[136]
2 shows an exemplary module case applicable in the present application.
[137]
3 schematically shows a form in which a battery cell is accommodated in a module case.
[138]
4 schematically shows an exemplary lower plate in which an injection hole and an observation hole are formed.
[139]
5 and 6 schematically illustrate an exemplary battery pouch that can be used as a battery cell.
[140]
7 and 8 schematically show the structure of an exemplary battery module.
[141]
References related to the drawings are as follows.
[142]
10: module case
[143]
10a: lower plate
[144]
10b: side wall
[145]
10c: top plate
[146]
10d: guiding part
[147]
20: battery cell
[148]
30: resin layer
[149]
50a: injection hole
[150]
50b: observation hall
[151]
40: insulating layer
[152]
100: pouch type cell
[153]
110: electrode assembly
[154]
120: exterior material
[155]
121: upper part
[156]
122: lower pouch
[157]
S: sealing part
Best mode for carrying out the invention
[158]
Hereinafter, the battery module of the present application will be described through Examples and Comparative Examples, but the scope of the present application is not limited by the ranges presented below.
[159]
Assessment Methods
[160]
1. Viscosity
[161]
The viscosity of the resin composition was measured under a shear rate condition of 0.01 to 10.0/s at room temperature using a rheological property analyzer (ARES). The viscosity mentioned in the examples is a viscosity at a shear rate of 2.5/s, and a thixotropic index (TI) can be determined through a ratio of the viscosity at a shear rate of 0.25/s and a point at 2.5/s.
[162]
2. Insulation performance
[163]
When each of the withstand voltage and the dielectric breakdown voltage described below satisfies a predetermined value, it is indicated as O, and if not, it is indicated as X.
[164]
(1) withstand voltage
[165]
Measured according to ISO 6469-3. Specifically, the composition was injected in a module state, and after 1 hour, 2kV was applied for 1 second, and if the leakage current was less than 1mA, it was marked as ○, and if it exceeded that, it was marked as X.
[166]
(2) Insulation breakdown voltage
[167]
Based on ASTM D149, a cured product with a thickness of 2 mm (stiffened) was prepared, and when the dielectric breakdown voltage was measured, if the value was 10 kV/mm or more, it was marked as ○, and if it was lower than this, it was marked as X.
[168]
3. Fairness
[169]
As a module case having the shape as shown in FIG. 1, a module case having a lower plate, sidewall and upper plate made of aluminum was used. A guiding part for guiding the installation of the battery cell is formed on the inner side of the lower plate of the module case, and injection holes for injection of the resin composition are formed at regular intervals in the center of the upper plate and the lower plate of the module case. , A case in which an observation hole is formed at the ends of the upper and lower plates was used. A bundle of pouches in which a plurality of battery pouches are stacked in the module case was accommodated. Then, the upper plate was covered on the upper surface of the module case.
[170]
(1) The resin composition was injected into each injection hole of the upper plate and the lower plate, and it was confirmed that the composition reached the observation hole. If the time it takes to reach the observation hole is less than 5 minutes, mark it as ○.If it exceeds this or does not have sufficient flowability to reach the observation hole, or due to too large flowability, the upper part of the gravitational direction within the module after injection If it is not evenly filled in each of the and lower parts, it is marked with an X.
[171]
(2) Composition injection (filling) After 1 hour, movement and vibration were applied to the module, and the composition was observed to flow out of the module. When there is no external contamination by the spilled composition, it is indicated by ○, and when there is contamination, it is indicated by X.
[172]
Examples to Comparative Examples
[173]
Example 1
[174]
Polyol: A caprolactone-based polyol represented by Chemical Formula 2 in the main composition, wherein the number of repeating units (m in Chemical Formula 2) is at a level of about 1 to 3, and 1,4- A resin containing a polyol containing butanediol (having a viscosity of about 280 cP as measured by a Brookfield LV type viscometer) was used in a predetermined amount.
[175]
Isocyanate: A mixture of HDI (Hexamethylene diisocyanate) and HDI trimer (having a viscosity of 170 cP when measured with a Brookfield LV type viscometer) was used for the curing agent composition. At this time, the amount of isocyanate compound used was adjusted so that the NCO index was about 100.
[176]
Filler: Alumina was used. The content was set to be a ratio of 1,000 parts by weight to 100 parts by weight of the total amount of the polyol and isocyanate, and the alumina was divided into equal amounts in the main composition part and the curing agent composition part.
[177]
Dispersant: An anionic dispersant was added in a predetermined amount.
[178]
Catalyst: dibutyltin dilaurate (DBTDL) was used in the amount shown in Table 1.
[179]
The components were mixed to prepare a two-part urethane-based composition.
[180]
Example 2
[181]
A composition was prepared in the same manner as in Example 1, except that the content of the dispersant was added at 70% relative to the content of the dispersant used in Example 1.
[182]
Example 3
[183]
The main composition part includes polydimethylsiloxane (PDMS) having a vinyl group, and the curing agent composition part includes polydimethylsiloxane having a vinyl group and polydimethylsiloxane having a hydryl group, and each viscosity is between 200,000 and 300,000. Blended with filler. During the mixing process, the amount of platinum catalyst used was appropriately adjusted.
[184]
Comparative Example 1
[185]
A composition was prepared in the same manner as in Example 1, except that the content of the catalyst was used at 30% compared to the content used in Example 1.
[186]
Comparative Example 2
[187]
A composition was prepared in the same manner as in Example 1, except that the content of the catalyst was used at a level three times that of the content used in Example 1.
[188]
Comparative Example 3
[189]
A composition was prepared in the same manner as in Example 1, except that the repeating unit m in Formula 2 of the subject composition was less than 1.
[190]
[Table 1]
[191]

[192]
[Table 2]
[193]

[194]
From Tables 1 and 2 above, it can be seen that the examples satisfying the viscosity-related conditions of the present application implement excellent fairness and insulation performance, but the fairness is not good in the case of the comparative examples in which the viscosity conditions are not satisfied. Specifically, if V3 is too low due to insufficient curing as in Comparative Example 1, contamination of adjacent parts or peeling of the adhesive surface may occur, and curing has already been performed at the time V2 is measured as in Comparative Example 2. If too much is made, it can be seen that the injection process is not good. And, if the viscosity related to V1 is too low as in Comparative Example 3, overflow occurs severely before curing progresses after injection, and the injected composition is cured evenly while flowing from the top to the bottom in the direction of gravity in the module. Rather than forming the resin layer, it is filled only in the lower portion of the gravity direction, and as a result, the upper portion in the gravity direction may be unfilled.
Claims
[Claim 1]
The initial viscosity change rate defined by the following relationship 1 is in the range of 1.1 to 5.0, the initial viscosity change rate defined by the following relationship 2 is 10 or more, and in the following relationship 1 and 2, V 1 is in the range of 100,000 to 500,000 cP, V 2 is 2,000,000 cP or less, and V 3 is a curable resin composition that satisfies 5,000,000 cP or more: [Relationship 1] Initial viscosity change rate = V 2 /V 1 [Relationship 2] Initial viscosity change rate = V 3 /V 1 (The above relational formula 1 In and 2, V 1 is the initial viscosity, the viscosity value measured at room temperature within 60 seconds after mixing the main material and the curing agent component of the resin composition, V 2 is the resin composition in which V 1 is measured is left at room temperature for 5 minutes V 3 is the viscosity value measured after V 1 is the viscosity measured after leaving the resin composition measured at room temperature for 60 minutes, V 1 To V 3 is a viscosity value measured at a point of 2.5/s when measured in a shear rate range of 0.01 to 10.0/s using a rheological property meter (ARES).)
[Claim 2]
The resin composition of claim 1, wherein the resin composition is a room temperature curing type, and the composition comprises a two-component silicone resin composition, a two-part urethane resin composition, a two-part epoxy resin composition, or a two-part acrylic resin composition.
[Claim 3]
The resin composition according to claim 2, wherein the cured product has a dielectric breakdown voltage of 10 kV/mm or more, measured after 24 hours have elapsed after mixing the main material and the curing agent.
[Claim 4]
The method of claim 2, wherein the resin composition is a two-component urethane-based composition, and the two-part urethane-based composition comprises an ester-based polyol resin-containing main composition; A polyisocyanate-containing curing agent composition portion; And a filler, wherein the ester-based polyol is an amorphous polyol whose crystallization temperature (Tc) and melting temperature (Tm) are not observed in DSC (Differential Scanning Calorimetry) analysis, or a resin composition having a melting temperature (Tm) of less than 15°C. .
[Claim 5]
The resin composition of claim 4, wherein the resin component has a glass transition temperature (Tg) of less than 0°C after curing.
[Claim 6]
The resin composition of claim 4, wherein each of the ester-based polyol resin and the polyisocyanate has a viscosity of less than 10,000 cP.
[Claim 7]
The method of claim 4, wherein the ester-based polyol is a resin composition represented by the following Formula 1 or 2: [Formula 1] [Formula 2] However, in Formulas 1 and 2, X is a carboxylic acid-derived unit, and Y is a polyol-derived unit And n is a number in the range of 2 to 10, and m is a number in the range of 1 to 10.
[Claim 8]
The carboxylic acid-derived unit X is phthalic acid unit, isophthalic acid unit, terephthalic acid unit, trimellitic acid unit, tetrahydrophthalic acid unit, hexahydrophthalic acid unit, tetrachlorophthalic acid unit, oxalic acid unit, adipic acid. Unit, azelaic acid unit, sebacic acid unit, succinic acid unit, malic acid unit, glataric acid unit, malonic acid unit, pimelic acid unit, suberic acid unit, 2,2-dimethylsuccinic acid unit, 3,3-dimethylglutaric acid A resin composition comprising at least one unit selected from the group consisting of units, 2,2-dimethylglutaric acid units, maleic acid units, fumaric acid units, itaconic acid units, and fatty acid units.
[Claim 9]
The method according to claim 7, wherein the polyol-derived unit Y is an ethylene glycol unit, a propylene glycol unit, a 1,2-butylene glycol unit, a 2,3-butylene glycol unit, a 1,3-propanediol unit, and 1,3. -Butanediol unit, 1,4-butanediol unit, 1,6-hexanediol unit, neopentyl glycol unit, 1,2-ethylhexyldiol unit, 1,5-pentanediol unit, 1,9-nonanediol unit, 1 ,10-decanediol unit, 1,3-cyclohexanedimethanol unit, 1,4-cyclohexanedimethanol unit, glycerin unit, and any one or two or more units selected from the group consisting of trimethylolpropane units .
[Claim 10]
The two-part urethane-based composition according to claim 4, wherein the polyisocyanate is a non-aromatic polyisocyanate.
[Claim 11]
The resin composition according to claim 10, wherein the non-aromatic polyisocyanate is an alicyclic polyisocyanate, a carbodiimide-modified polyisocyanate of an alicyclic polyisocyanate, or an isocyanurate-modified polyisocyanate of an alicyclic polyisocyanate.
[Claim 12]
The resin composition of claim 4, wherein the filler includes alumina, aluminum nitride (AlN), boron nitride (BN), silicon nitride, SiC, or BeO.
[Claim 13]
The resin composition according to claim 4, comprising 50 to 2,000 parts by weight of a filler based on 100 parts by weight of the total amount of the ester-based polyol resin and polyisocyanate.
[Claim 14]
A module case having an upper plate, a lower plate, and sidewalls, wherein an inner space is formed by the upper plate, the lower plate, and the sidewall; A plurality of battery cells present in the inner space of the module case; And a resin layer formed by curing the composition according to claim 1 and in contact with the plurality of battery cells.
[Claim 15]
A battery pack comprising one or more other battery modules according to claim 14.
[Claim 16]
A vehicle comprising the battery module according to claim 14 or the battery pack according to claim 15.