Thermally conductive composition, thermally conductive member, battery module

Abstract

The present application is a thermally conductive composition comprising (A) an organopolysiloxane having at least 2 alkenyl groups, (B) a hydrogenated organopolysiloxane having at least 2 hydrosilyl groups, (C) a thermally conductive filler, and (D) a polysiloxane compound having at least one alkyl group having 4 or more carbon atoms. According to the present application, it is possible to provide a thermally conductive composition capable of forming a thermally conductive member having excellent thermal conductivity and high adhesion to polypropylene.

Description

Technical Field

[0001] This invention relates to a thermally conductive composition, a thermally conductive component, and a battery module using the thermally conductive component as a gap material. Background Technology

[0002] A cured product is formed by filling a heat-generating element and a heat-dissipating element with a curable thermally conductive composition and then curing it. This cured product is used as a thermally conductive member to transfer heat emitted by the heat-generating element to the heat-dissipating element. Because the curable thermally conductive composition has fluidity, it can fill any gap between the heat-generating element and the heat-dissipating element. Therefore, the formed thermally conductive member can reliably fill the gap between the heat-generating element and the heat-dissipating element even if the gap is not necessarily fixed, and can be used as a thermally conductive gap material.

[0003] For example, as disclosed in Patent Document 1, it is known to use thermally conductive members as gap materials in battery modules. The thermally conductive members are disposed between the battery cells, which act as heat generators, and the module housing, which acts as heat sinks, to dissipate heat from the battery cells to the outside. Furthermore, they are also used to fix battery cells together, keeping them in a separated state.

[0004] Thermally conductive components have a certain degree of adhesion, and are often tightly fitted to prevent them from shifting or falling off from the adhered objects such as the heating element and the heat sink. In cases where they are fixed more firmly, the heating element and the heat sink are also fitted together or fixed with screws or the like.

[0005] However, when using thermally conductive components for automotive applications, even with a certain degree of adhesion, there is a concern that vibration could cause them to peel off from the adhered materials such as heat-generating and heat-dissipating elements, impairing thermal conductivity. Based on this understanding, Patent Document 2 discloses a thermally conductive composition comprising a curable organopolysiloxane, an alkoxysilane compound, and a thermally conductive filler, wherein the alkoxysilane compound is an alkoxysilane containing a long-chain alkenyl group with 8 to 18 carbon atoms, and describes that it exhibits excellent adhesion to adhered materials.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2018 / 173860

[0009] Patent Document 2: International Publication No. 2020 / 213306 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] Previously, high-reliability metals such as aluminum alloys were used in the casing of lithium-ion battery modules. However, in recent years, from the perspective of lightweighting and cost reduction, polypropylene, a cheaper general-purpose resin, has been used, which has certain heat resistance, toughness, and lightweight properties.

[0012] However, it is known that the thermally conductive components used in the past have weak adhesion to polypropylene, and defects such as peeling are prone to occur.

[0013] Therefore, the objective of this invention is to provide a thermally conductive composition capable of forming a thermally conductive component with excellent thermal conductivity and high adhesion to polypropylene.

[0014] Methods for solving problems

[0015] The inventors conducted in-depth research and found that the above-mentioned problems can be solved by a thermally conductive composition comprising (A) an organopolysiloxane having at least two alkenyl groups, (B) a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups, (C) a thermally conductive filler material, and (D) a polysiloxane compound having at least one alkyl group having four or more carbon atoms, thereby completing the following invention. That is, the present invention provides the following [1] to [8].

[0016] [1] A thermally conductive composition comprising: (A) an organopolysiloxane having at least two alkenyl groups; (B) a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups; (C) a thermally conductive filler material; and (D) a polysiloxane compound having at least one alkyl group having four or more carbon atoms.

[0017] [2] According to the thermally conductive composition described in [1] above, the (D) polysiloxane compound has a reactive group capable of reacting with the (A) component or (B) component above.

[0018] [3] In the thermally conductive composition described in [1] or [2] above, the reactive group is (meth)acryloyl.

[0019] [4] In the thermally conductive composition according to any one of [1] to [3] above, the number of carbon atoms of the alkyl group in the (D) polysiloxane compound is 4 or more and 30 or less.

[0020] [5] In the thermally conductive composition according to any one of [1] to [4] above, the number of carbon atoms of the alkyl group in the (D) polysiloxane compound is 4 or more and 8 or less.

[0021] [6] In any one of the thermally conductive compositions described in [1] to [5] above, the alkyl group of the (D) polysiloxane compound is butyl.

[0022] [7] A thermally conductive component, which is formed by curing the thermally conductive composition described in any one of [1] to [6] above.

[0023] [8] A battery module comprising a gap material made of the thermally conductive member described above [7], a plurality of battery cells, and a module housing for storing the plurality of battery cells, wherein the gap material is disposed inside the module housing.

[0024] The effects of the invention

[0025] According to the present invention, a thermally conductive composition can be provided that can form a thermally conductive component with excellent thermal conductivity and high adhesion to polypropylene. Attached Figure Description

[0026] Figure 1 A perspective view showing a representative configuration of the battery module involved in this invention.

[0027] Figure 2 A three-dimensional view showing a representative configuration of the battery cells in a battery module. Detailed Implementation

[0028] [Thermal Conductivity Composition]

[0029] The thermally conductive composition of the present invention will now be described in detail.

[0030] The thermally conductive composition of the present invention comprises (A) an organopolysiloxane having at least two alkenyl groups, (B) a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups, (C) a thermally conductive filler material, and (D) a polysiloxane compound having at least one alkyl group having four or more carbon atoms. The thermally conductive component of the present invention is formed by curing the thermally conductive composition.

[0031] The reason for the high adhesion of the thermally conductive member formed by the thermally conductive composition of the present invention to polypropylene is uncertain, but it is presumed as follows: (D) The polysiloxane compound, due to its polysiloxane structure, is compatible with the organosilicon matrix formed by the reaction of components (A) and (B). Furthermore, the (D) polysiloxane compound possesses alkyl groups with 4 or more carbon atoms, thereby exhibiting high affinity for polypropylene. As a result, the surface energy of the organosilicon matrix constituting the thermally conductive member is considered to be reduced, and the adhesion to polypropylene is increased.

[0032] <Component A, Component B>

[0033] The thermally conductive composition of the present invention contains (A) an organopolysiloxane having at least two alkenyl groups (hereinafter also referred to as component (A)) and (B) a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups (hereinafter also referred to as component (B)). It should be noted that components (A) and (B) are different from component (D) described later.

[0034] Component (A) is generally used as the main agent, and component (B) is generally used as the curing agent. Components (A) and (B) react and cure through an addition reaction to form a matrix made of silicone rubber. Because silicone rubber is easily compressed and deformed, the thermally conductive component of the present invention is easily assembled between a heat-generating element and a heat-dissipating element.

[0035] (A) There are no particular restrictions as long as the component is an organopolysiloxane having at least two alkenyl groups in one molecule. The number of alkenyl groups in one molecule of (A) is preferably 2 to 20, more preferably 2 to 10.

[0036] Examples of alkenyl groups in component (A) include alkenyl groups with 2 to 8 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, etc.

[0037] (A) You may use only one ingredient or use two or more ingredients together.

[0038] (B) There are no particular restrictions as long as the component is a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups per molecule. A hydrogenated silyl group refers to a hydrogen atom bonded to a silicon atom (SiH group). The number of hydrogenated silyl groups per molecule of (B) is preferably 2 to 100, more preferably 2 to 50.

[0039] (B) One ingredient may be used, or two or more ingredients may be used together.

[0040] As component (B), it is preferred to include (B) X Hydrogenated organopolysiloxanes (hereinafter referred to as (B)) containing 2 mmol / g or more of hydrogenated silanes. X (Composition). As a result, the hardness of the formed thermally conductive component is increased, and the adhesion to polypropylene is easily improved.

[0041] (B X The content of the hydrogenated silane in the component is preferably 4 mmol / g or more, more preferably 6 mmol / g or more.

[0042] (B X The content of the component can be adjusted in a way that achieves the desired hardness of the cured product. (B) X The amount of component ) is sufficient. Specifically, simply increase (B) when you want the cured material to harden. XThe content of component (B) is adjusted to make the cured material softer. X The content of the ingredient should be low.

[0043] Components (A) and (B) are preferably in a liquid state before curing. Being in a liquid state before curing facilitates the filling of thermally conductive filler materials. It should be noted that, in this specification, "liquid state" refers to a substance that is liquid at room temperature (23°C) and 1 atmosphere. The addition reaction of components (A) and (B) is preferably carried out in the presence of an addition reaction catalyst, preferably a platinum catalyst.

[0044] <(C) Ingredients>

[0045] The thermally conductive composition of the present invention contains a thermally conductive filler material (C). By containing the thermally conductive filler material (C), the thermal conductivity of the thermally conductive member formed by the thermally conductive composition is improved.

[0046] Examples of thermally conductive fillers (C) include metals, metal oxides, metal nitrides, metal hydroxides, carbon materials, oxides other than metals, nitrides, carbides, etc. Furthermore, examples of thermally conductive fillers (C) include spherical or amorphous powders.

[0047] In (C) the thermally conductive filler material, examples of metals include aluminum, copper, and nickel; examples of metal oxides include aluminum oxide (represented by aluminum oxide), magnesium oxide, and zinc oxide; and examples of metal nitrides include aluminum nitride. Aluminum hydroxide is an example of a metal hydroxide. Furthermore, spherical graphite is an example of a carbon material. Examples of oxides, nitrides, and carbides other than metals include quartz, boron nitride, and silicon carbide. Among these, aluminum oxide is preferred from the viewpoint of improving the heat dissipation of the thermally conductive component, and aluminum hydroxide is preferred when improving flame retardancy.

[0048] (C) Thermally conductive filler materials may use one of the above substances alone or in combination with two or more substances.

[0049] (C) The average particle size of the thermally conductive filler material is preferably 0.1 to 200 μm, more preferably 0.5 to 100 μm, and even more preferably 1 to 70 μm.

[0050] (C) The thermally conductive filler material preferably comprises a combination of a small-particle-size thermally conductive filler material with an average particle size of 0.1 μm or more and 5 μm or less, and a large-particle-size thermally conductive filler material with an average particle size of more than 5 μm and 200 μm or less. By using thermally conductive fillers with different average particle sizes, the filler ratio can be improved. The volume ratio of the small-particle-size thermally conductive filler material to the large-particle-size thermally conductive filler material (small-particle-size thermally conductive filler material / large-particle-size thermally conductive filler material) is preferably 0.05 to 5, more preferably 0.1 to 1, and even more preferably 0.2 to 0.8.

[0051] It should be noted that the average particle size of the (C) thermally conductive filler material can be determined by observation using an electron microscope or similar method. More specifically, by using, for example, an electron microscope or an optical microscope, the particle size of any 50 (C) thermally conductive fillers can be measured, and their average value (arithmetic mean) can be taken as the average particle size.

[0052] The content of the thermally conductive filler (C) relative to the total of 100 parts by mass of component (A), component (B), and polysiloxane compound (D) is preferably 150 to 3000 parts by mass, more preferably 200 to 2000 parts by mass, and even more preferably 300 to 1000 parts by mass. By ensuring that the content of the thermally conductive filler (C) is at or above the aforementioned lower limit, a certain thermal conductivity can be imparted to the thermally conductive component. By ensuring that the content of the thermally conductive filler (C) is below or above the aforementioned upper limit, the thermally conductive filler (C) can be appropriately dispersed in the thermally conductive component. Furthermore, it is also possible to prevent the viscosity of the thermally conductive composition from becoming excessively high.

[0053] <(D) component>

[0054] The thermally conductive composition of the present invention contains (D) a polysiloxane compound having at least one alkyl group having four or more carbon atoms ((D) polysiloxane compound). By containing the (D) polysiloxane compound, the adhesion of the thermally conductive member formed by the thermally conductive composition to polypropylene is improved.

[0055] (D) The polysiloxane compound may have at least one alkyl group with 4 or more carbon atoms, but from the viewpoint of adhesion to polypropylene and ease of manufacturing of the compound, the number of alkyl groups with 4 or more carbon atoms in (D) the polysiloxane compound is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1.

[0056] Alkyl groups with 4 or more carbon atoms are not particularly limited in that they can be linear or branched. Preferably, the alkyl group with 4 or more carbon atoms has 4 or more and 30 or less carbon atoms, more preferably 4 or more and 12 or less carbon atoms, even more preferably 4 or more and 8 or less carbon atoms, and particularly preferably 4 carbon atoms. That is, butyl is particularly preferred as an alkyl group with 4 or more carbon atoms.

[0057] In the case where (D) polysiloxane compounds have multiple alkyl groups having 4 or more carbon atoms, these multiple alkyl groups having 4 or more carbon atoms may be the same or different.

[0058] From the viewpoint of improving the adhesion of polypropylene, when there is one alkyl group with 4 or more carbon atoms, it is preferable that the alkyl group with 4 or more carbon atoms is present at the end of the (D) polysiloxane compound. When there are two or more alkyl groups with 4 or more carbon atoms, it is preferable that at least one alkyl group with 4 or more carbon atoms is present at the end of the (D) polysiloxane compound.

[0059] Furthermore, the (D) polysiloxane compound preferably possesses reactive groups capable of reacting with either component (A) or (B) described above. Thus, because the (D) polysiloxane compound readily bonds with components (A) and (B) through chemical bonds, the surface energy of the silicone matrix is ​​easily reduced. Further, as described above, the (D) polysiloxane compound, having alkyl groups with 4 or more carbon atoms, exhibits enhanced affinity between the silicone matrix and polypropylene, resulting in excellent adhesion between the two.

[0060] The reactive group capable of reacting with component (A) or component (B) is not particularly limited, but is preferably selected from (meth)acryloyl, alkenyl, and silyl (SiH) groups. (Methacryl)acryloyl and alkenyl are reactive groups capable of reacting with component (B), and silyl (SiH) groups are reactive groups capable of reacting with component (A).

[0061] (Methyl)acryloyl refers to acryloyl or methacryloyl.

[0062] Examples of alkenyl groups include those with 2 to 8 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl.

[0063] Among these reactive groups, (meth)acryloyl group is preferred, and methacryloyl group is more preferred.

[0064] When the (D) polysiloxane compound has reactive groups, the number of reactive groups in the (D) polysiloxane compound can be one or more, but preferably one.

[0065] The (D) polysiloxane compound in this invention is preferably a compound represented by the following formula (1).

[0066]

[0067] X is an organic group with a reactive group. At least one of B, C, and D is a group represented by the following formula (2), and the rest are methyl or phenyl. When there are multiple groups represented by formula (2), the multiple groups represented by formula (2) may be the same or different. Preferably, one or two of B, C, and D are groups represented by the following formula (2), and the rest are methyl.

[0068]

[0069] R1 and R2 are each independently methyl or phenyl. At least one of R3, R4, and R5 is an alkyl group having 4 or more carbon atoms, and the others are each independently methyl, phenyl, or X (i.e., an organogroup having the above-mentioned reactive group), preferably the others are each independently methyl or phenyl. * refers to the bonding bond with Si in formula (1). n is an integer from 9 to 130.

[0070] Preferably, R3 is an alkyl group with 4 or more carbon atoms, and R4 and R5 are each independently methyl or phenyl, more preferably both R4 and R5 are methyl.

[0071] The alkyl group having 4 or more carbon atoms preferably has 4 or more and 30 or less carbon atoms, more preferably 4 or more and 12 or less, even more preferably 4 or more and 8 or less, and particularly preferably 4. That is, butyl is particularly preferred as an alkyl group having 4 or more carbon atoms.

[0072] The reactive group X is the same as the reactive group described above that is capable of reacting with component (A) or component (B). X is preferably an organogroup having 2 to 50 carbon atoms, and more preferably an organogroup having 3 to 15 carbon atoms.

[0073] X is preferably any one of the following X1 to X6.

[0074]

[0075] In X1 to X6 above, A is a reactive group. A is preferably a reactive group selected from (meth)acryloyl, alkenyl, and silylhydride (SiH), more preferably (meth)acryloyl, and even more preferably methacryloyl. n1 is an integer from 1 to 2. n2 is an integer from 1 to 6, preferably an integer from 2 to 4. * indicates a bonding bond with Si in formula (1).

[0076] Of the above X1 to X6, from the viewpoint of improving the adhesion of the thermally conductive component to polypropylene, X is preferably X2.

[0077] The content of the (D) polysiloxane compound in the thermally conductive composition is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 10 parts by mass, relative to a total of 100 parts by mass of components (A), (B), and (D) polysiloxane compound. By setting the content of the (D) polysiloxane compound within the above range, the adhesion of the thermally conductive component formed from the thermally conductive composition to polypropylene is easily improved.

[0078] The thermally conductive composition of the present invention may contain various additives. Examples of additives include catalysts, dispersants, flame retardants, plasticizers, curing delay agents, antioxidants, colorants, etc.

[0079] The thermally conductive composition of the present invention can be a single-component type or a two-component type consisting of a first agent and a second agent, but from the viewpoint of storage stability, a two-component type is preferred.

[0080] In the two-component thermally conductive composition, the mass ratio of the first agent to the second agent (second agent / first agent) is preferably 1 or close to 1, specifically, preferably 0.9 to 1.1, more preferably 0.95 to 1.05. This makes the preparation of the thermally conductive composition easier by setting the mass ratio of the first agent to the second agent to 1 or close to 1. Furthermore, in the two-component thermally conductive composition, the viscosity ratio of the first agent to the second agent (second agent / first agent) is also preferably 1 or close to 1, specifically preferably 0.5 to 2.0, more preferably 0.8 to 1.2. This makes it easier to uniformly mix the thermally conductive composition by setting the mass ratio of the first agent to the second agent to 1 or close to 1. It should be noted that the methods for adjusting the mass ratio and viscosity ratio will be described later.

[0081] More specifically, the two-component thermally conductive composition comprises (A) an organopolysiloxane having at least two alkenyl groups (component A) (main agent) and (B) a hydrogenated organopolysiloxane having at least two hydrogenated silyl groups (component B) (curing agent).

[0082] The addition reaction catalyst is preferably included in the first agent and not in the second agent. This ensures that the first and second agents maintain excellent stability before mixing, and that the reaction is promoted and rapidly cured after mixing, resulting in a thermally conductive component with good physical properties obtained through curing. The main reason for this is uncertain, but it is presumed that curing is facilitated by the state where the addition reaction catalyst, such as a platinum catalyst, is coordinated with the alkenyl group at the addition reaction site of component (A).

[0083] (C) It is preferable that the thermally conductive filler material is included in at least one of the first agent and the second agent, but it is more preferably included in both the first agent and the second agent. If the thermally conductive filler material (C) is included in both the first agent and the second agent, it is easy to mix the first agent and the second agent. In addition, since the mass ratio and viscosity ratio of the second agent to the first agent when making the thermally conductive composition can be 1 or close to 1, it is easy to use as a two-component type.

[0084] Furthermore, the second agent preferably contains component (A). By including component (A) as a main agent in addition to component (B) as a curing agent, the mass ratio and viscosity ratio of the second agent relative to the first agent when preparing the thermally conductive composition are easily adjusted to a value of 1 or close to 1. On the other hand, it is preferable that the first agent does not contain component (B) as a curing agent.

[0085] When the second agent is used in the form of containing component (A) and a trace amount of addition reaction catalyst in addition to component (B), in order to prevent the addition reaction from solidifying during storage, a curing delay agent is added to counteract the reaction-promoting effect at room temperature caused by the addition reaction catalyst added to the second agent, thereby achieving a state that substantially does not contain the addition reaction catalyst.

[0086] Specifically, when the second agent contains a trace amount of addition reaction catalyst, a curing delay agent can be added during storage to suppress the reaction between component (B) and component (A) caused by the addition reaction catalyst. Examples of curing delay agents include alcohol derivatives with carbon-carbon triple bonds such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, phenylbutynol, and 1-ethynyl-1-cyclohexanol; alkenyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; low molecular weight siloxanes containing alkenyl groups such as tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane; and silanes containing alkynes such as methyl-tris(3-methyl-1-butyn-3-oxy)silane and vinyl-tris(3-methyl-1-butyn-3-oxy)silane.

[0087] In addition, the second agent may contain an amount of addition reaction catalyst that does not promote the reaction at room temperature, even if it does not contain a curing delay agent.

[0088] Platinum catalysts, such as chloroplatinic acid and coordination compounds of chloroplatinic acid with olefins, vinylsiloxanes, or acetylene compounds, which are used as addition reaction catalysts, act on component (B) as a curing agent, thereby enhancing its reactivity. As a means to prevent unwanted activation of the curing agent during storage, it is most effective to ensure that the second agent does not contain an addition reaction catalyst.

[0089] The (D) polysiloxane compound may be contained in either agent 1 or agent 2, or in both. When the (D) polysiloxane compound possesses a reactive group capable of reacting with component (A) or component (B), from the viewpoint of preserving stability, it is preferable to determine the mixing method of the (D) polysiloxane compound based on the type of reactive group.

[0090] When the reactive group of the (D) polysiloxane compound is a group capable of reacting with component (B) (e.g., (meth)acryloyl or alkenyl), from the viewpoint of storage stability, the (D) polysiloxane compound is preferably mixed with the first agent. Furthermore, when the reactive group of the (D) polysiloxane compound is a group capable of reacting with component (A) (e.g., hydrosilyl), from the viewpoint of storage stability, the (D) polysiloxane compound is preferably mixed with the second agent.

[0091] The curing temperature of the thermally conductive composition can be selected based on the type and amount of component (B) used as a curing agent, as well as the type and amount of addition reaction catalyst added. For example, in a two-component type, it is acceptable as long as the first and second agents can be cured simply by mixing and leaving at room temperature, but it is also possible to choose a form in which curing is promoted by heating.

[0092] [Thermal conductive components]

[0093] By curing the thermally conductive composition of the present invention, a thermally conductive component can be formed. The hardness of the thermally conductive component (i.e., the cured product of the thermally conductive composition), measured by a hardness tester of type E of JIS K 6253 (hereinafter referred to as "E hardness"), is, for example, 30 to 90, preferably 35 to 80, and more preferably 40 to 70.

[0094] By setting the E-hardness of the thermally conductive component to the lower limit value or above, the adhesion between the thermally conductive component and the polypropylene is improved. This is presumably because the thermally conductive component possesses a certain degree of hardness, thus suppressing agglomeration and breakage. Furthermore, by setting the E-hardness of the thermally conductive component to the upper limit value or below, sufficient flexibility to conform well to the shape of the heating element and the heat sink, as well as good adhesion to the heating element and the heat sink, can be ensured.

[0095] The thermal conductivity of the thermally conductive component (i.e., the cured form of the thermally conductive composition) is preferably 1.0 W / m·K or higher, more preferably 1.5 W / m·K or higher, and even more preferably 2.0 W / m·K or higher. By being above these lower limits, the thermal conductivity becomes good. Therefore, when used, for example, as a gap material in a battery cell module, heat generated from the battery cell can be efficiently transferred to the module housing via the gap material, and excessive temperature rise of the battery cell can be suppressed. Higher thermal conductivity of the thermally conductive component is better, but in practical applications, it is, for example, 7 W / m·K or lower.

[0096] [Battery Module]

[0097] The battery module of the present invention comprises a gap material made of a thermally conductive member, a plurality of battery cells, and a module housing for storing the plurality of battery cells, wherein the gap material is disposed inside the module housing.

[0098] A spacer material, composed of thermally conductive components, is filled between the battery cells and between the battery cells and the module housing, ensuring a tight seal between the spacer material and both the battery cells and the module housing. Thus, the spacer material between the battery cells functions to maintain the separation between them. Furthermore, the spacer material between the battery cells and the module housing, being tightly sealed to both, functions to transfer heat generated by the battery cells to the module housing.

[0099] Figure 1 This shows the specific composition of the battery module. Figure 2 This shows the specific composition of each battery cell. For example... Figure 1 As shown, multiple battery cells 11 are arranged inside the battery module 10. Each battery cell 11 is a material laminated and sealed within a flexible outer film, and its overall shape is a flat body that is thin compared to its height and width. Such a battery cell 11 is as follows: Figure 2 As shown, the positive electrode 11a and the negative electrode 11b are exposed to the outside, and the central portion 11c of the flat surface is formed with a wall thickness compared to the crimped end 11d.

[0100] like Figure 1 As shown, the battery cells 11 are arranged with their flat surfaces facing each other. Figure 1 In this configuration, the gap material 13 is not filled in a manner that covers the entirety of the plurality of battery cells 11 stored inside the module housing 12. Instead, the gap material 13 is filled in a manner that fills the gaps in a portion (bottom side portion) of the interior of the module housing 12. The gap material 13 is filled between the battery cells 11 and between the battery cells 11 and the module housing 12, and is in close contact with the surface of the battery cells 11 in that portion and the inner surface of the module housing 12.

[0101] The gap material 13, which is filled between the battery cells 11, is bonded to the surfaces of the two battery cells 11. However, the gap material 13 itself has the aforementioned hardness, thus possessing moderate elasticity and flexibility. Even if an external force is applied that causes the battery cells 11 to shift apart, the strain deformation caused by the external force can be mitigated. Therefore, the gap material 13 has the function of maintaining the separation between the battery cells 11.

[0102] The gap material 13, which fills the gap between the battery cell 11 and the inner surface of the module housing 12, is also tightly bonded to the surface of the battery cell 11 and the inner surface of the module housing 12. As a result, the heat generated inside the battery cell 11 is transferred through the gap material 13 bonded to the surface of the battery cell 11 to the inner surface of the module housing 12, which is sealed through the other surfaces of the gap material 13.

[0103] The formation of the gap material 13 within the battery module 10 is preferably carried out by applying a liquid thermally conductive composition using a conventional dispenser and then allowing the liquid thermally conductive composition to solidify. At this time, as described above, a two-component thermally conductive composition is preferred. Two-component compositions are easy to store, and if mixed just before use, they are less likely to solidify during the application process using a dispenser; however, they can be rapidly solidified after application. Furthermore, the application using a dispenser is preferred in that the liquid thermally conductive composition can fill to a considerable depth within the housing 12 of the battery module 10.

[0104] The gap material 13 covering the battery cell 11 is preferably located on one side of the battery cell 11, covering 20% ​​to 40% of each battery cell 11. A coverage of 20% or more ensures stable holding of the battery cell 11. Furthermore, by adequately covering the battery cell that generates significant heat, heat dissipation efficiency is improved. On the other hand, a coverage of 40% or less allows for efficient heat dissipation from the battery cell 11, preventing increased weight and deterioration of workability. Moreover, to ensure good heat dissipation efficiency, it is preferable to cover the side of the battery cell 11 containing the electrodes 11a and 11b with the gap material 13, and more preferably, to cover the entire electrodes 11a and 11b with the gap material 13.

[0105] As described above, the battery module 10 can release the heat generated from the battery cell 11 to the module housing 12 via the gap material 13.

[0106] The gap material 13 is also preferably used in battery packs that have multiple battery modules 10 inside. A battery pack generally has multiple battery modules 10 and a housing that houses the multiple battery modules 10. In this battery pack, the gap material 13 can be provided between the battery modules 10 and the battery pack housing. Therefore, as described above, the heat released to the module housing 12 can be further released to the battery pack housing, enabling effective heat dissipation.

[0107] Furthermore, since the gap material 13 uses the thermally conductive component of the present invention, the adhesion is good even if the module housing 12 or the battery pack housing is made of polypropylene. Therefore, the thermally conductive component of the present invention is less likely to detach from the module housing 12 or the battery pack housing even when subjected to vibration or impact during the starting, stopping, and driving of the vehicle, and can maintain good heat dissipation.

[0108] Example

[0109] The present invention will be further described in detail below by way of examples, but the present invention is not limited by these examples.

[0110] Tensile shear bond strength

[0111] Tensile shear bond strength is evaluated by measuring tensile shear strength as follows.

[0112] Tensile shear strength was determined according to the tensile shear test of JIS K6850:1999. Two test pieces were prepared: an aluminum plate (100 mm long, 25 mm wide, and 2 mm thick) and a polypropylene plate, arranged so that their front ends overlapped at a length of 25 mm × 25 mm. A liquid thermally conductive composition with a thickness of 2 mm was applied between them, and the mixture was left to cure at 25°C for 24 hours. Then, a tensile test was performed using a tensile testing machine (Toyo Seiki Co., Ltd. "STROGRAPH VE50") at room temperature (25°C) and a tensile speed of 100 mm / min. The tensile shear strength was measured, and the point where the tensile shear strength was maximum was used as the evaluation of the tensile shear bond strength.

[0113] [E Hardness]

[0114] The thermal conductivity of the component was determined using a JIS K 6253 type E hardness tester.

[0115] Thermal conductivity

[0116] The thermally conductive component was cut into plates with a thickness of 20 mm, and its thermal conductivity was determined based on ASTM D5470.

[0117] [Examples 1-3, 7-9]

[0118] Agent 1 and Agent 2, with the following compositions, were prepared and mixed at a mass ratio of 1:1 to obtain a thermally conductive composition with the composition described in Table 1. The obtained thermally conductive composition was left at room temperature (23°C) for 24 hours to cure, thereby obtaining a thermally conductive component.

[0119] <Dose 1>

[0120] • Organopolysiloxane A having at least 2 alkenyl groups

[0121] The polysiloxane compound D1 with the structure shown in formula (3) below

[0122]

[0123] n=63, molecular weight 5,000

[0124] • Aluminum hydroxide C1 (average particle size 1 μm)

[0125] • Aluminum hydroxide C2 (average particle size 54 μm)

[0126] • Trace amounts of platinum catalyst

[0127] <Second dose>

[0128] • Organopolysiloxane A having at least 2 alkenyl groups

[0129] • Hydrogenated organopolysiloxane B1 having at least two hydrogenated silane groups

[0130] • Hydrogenated organopolysiloxane B2 having at least two hydrogenated silane groups

[0131] • Aluminum hydroxide C1 (average particle size 1 μm)

[0132] • Aluminum hydroxide C2 (average particle size 54 μm)

[0133] It should be noted that hydrogenated organopolysiloxanes B1 and B2 are curing agents with different SiH group contents. The SiH group content of hydrogenated organopolysiloxane B2 is 7 mmol / g, and the viscosity is 30 cSt.

[0134] [Examples 4-6]

[0135] Agent 1 and Agent 2, with the following compositions, were prepared and mixed at a mass ratio of 1:1 to obtain a thermally conductive composition with the composition described in Table 1. The obtained thermally conductive composition was left at room temperature (23°C) for 24 hours to cure, thereby obtaining a thermally conductive component.

[0136] <Dose 1>

[0137] • Organopolysiloxane A having at least 2 alkenyl groups

[0138] The polysiloxane compound D2 with the structure shown in formula (4) below

[0139]

[0140] n = 130, molecular weight 10,000

[0141] • Aluminum hydroxide C1 (average particle size 1 μm)

[0142] • Aluminum hydroxide C2 (average particle size 54 μm)

[0143] • Trace amounts of platinum catalyst

[0144] <Second dose>

[0145] • Organopolysiloxane A having at least 2 alkenyl groups

[0146] • Hydrogenated organopolysiloxane B1 having at least two hydrogenated silane groups

[0147] • Hydrogenated organopolysiloxane B2 having at least two hydrogenated silane groups

[0148] • Aluminum hydroxide C1 (average particle size 1 μm)

[0149] • Aluminum hydroxide C2 (average particle size 54 μm)

[0150] [Comparative Example 1]

[0151] Agent 1 and Agent 2, with the following compositions, were prepared and mixed at a mass ratio of 1:1 to obtain a thermally conductive composition with the composition described in Table 1. The obtained thermally conductive composition was left at room temperature (23°C) for 24 hours to cure, thereby obtaining a thermally conductive component.

[0152] <Dose 1>

[0153] • Organopolysiloxane A having at least 2 alkenyl groups

[0154] • Aluminum hydroxide C1 (average particle size 1 μm)

[0155] • Aluminum hydroxide C2 (average particle size 54 μm)

[0156] • Trace amounts of platinum catalyst

[0157] <Second dose>

[0158] • Organopolysiloxane A having at least 2 alkenyl groups

[0159] • Hydrogenated organopolysiloxane B1 having at least two hydrogenated silane groups

[0160] • Aluminum hydroxide C1 (average particle size 1 μm)

[0161] • Aluminum hydroxide C2 (average particle size 54 μm)

[0162] [Comparative Example 2]

[0163] Agent 1 and Agent 2, with the following compositions, were prepared and mixed at a mass ratio of 1:1 to obtain a thermally conductive composition with the composition described in Table 1. The obtained thermally conductive composition was left at room temperature (23°C) for 24 hours to cure, thereby obtaining a thermally conductive component.

[0164] <Dose 1>

[0165] • Organopolysiloxane A having at least 2 alkenyl groups

[0166] • Aluminum hydroxide C1 (average particle size 1 μm)

[0167] • Aluminum hydroxide C2 (average particle size 54 μm)

[0168] • Trace amounts of platinum catalyst

[0169] <Second dose>

[0170] • Organopolysiloxane A having at least 2 alkenyl groups

[0171] • Hydrogenated organopolysiloxane B1 having at least two hydrogenated silane groups

[0172] • Hydrogenated organopolysiloxane B2 having at least two hydrogenated silane groups

[0173] • Aluminum hydroxide C1 (average particle size 1 μm)

[0174] • Aluminum hydroxide C2 (average particle size 54 μm)

[0175] [Comparative Example 3]

[0176] Agent 1 and Agent 2, with the following compositions, were prepared and mixed at a mass ratio of 1:1 to obtain a thermally conductive composition with the composition described in Table 1. The obtained thermally conductive composition was left at room temperature (23°C) for 24 hours to cure, thereby obtaining a thermally conductive component.

[0177] <Dose 1>

[0178] • Organopolysiloxane A having at least 2 alkenyl groups

[0179] • As a comparative compound, a polydimethylsiloxane without an alkyl group having more than 4 carbon atoms and having 2 methacrylate groups (a comparative compound of (D)polysiloxane compounds)

[0180] • Aluminum hydroxide C1 (average particle size 1 μm)

[0181] • Aluminum hydroxide C2 (average particle size 54 μm)

[0182] • Trace amounts of platinum catalyst

[0183] <Second dose>

[0184] • Organopolysiloxane A having at least 2 alkenyl groups

[0185] • Hydrogenated organopolysiloxane B1 having at least two hydrogenated silane groups

[0186] • Hydrogenated organopolysiloxane B2 having at least two hydrogenated silane groups

[0187] • Aluminum hydroxide C1 (average particle size 1 μm)

[0188] • Aluminum hydroxide C2 (average particle size 54 μm)

[0189] [Table 1]

[0190]

[0191] The thermally conductive components of Examples 1-9, formed from the thermally conductive compositions of the present invention containing (D) polysiloxane compounds, exhibit high tensile shear bond strength and excellent adhesion to polypropylene. Furthermore, comparing Examples 1-3 and Examples 4-6 with the same amount of (D) polysiloxane compounds, it is evident that a higher E-hardness value in the thermally conductive component leads to increased tensile shear bond strength and improved adhesion to polypropylene.

[0192] On the other hand, it can be seen that the tensile shear bond strength of the thermally conductive components formed by the thermally conductive compositions of Comparative Examples 1 to 3, which do not contain (D) polysiloxane compounds, is lower, and the adhesion to polypropylene is reduced.

[0193] Explanation of symbols

[0194] 10 Battery Modules

[0195] 11 Battery cells

[0196] 12. Battery module housing (module housing)

[0197] 13. Gap material.

Claims

1. A two-component thermally conductive composition comprising a first agent and a second agent, The first agent comprises (A) an organopolysiloxane having at least two alkenyl groups, (C) a thermally conductive filler material, and an addition reaction catalyst. The second agent comprises (B) a hydrogenated organopolysiloxane having at least two hydrogenated silane groups, and (C) a thermally conductive filler material, and does not contain an addition reaction catalyst. The first agent and the second agent, or both of them, contain (D) a polysiloxane compound having at least one alkyl group having 4 or more and 30 or fewer carbon atoms. The (D) polysiloxane compound has reactive groups capable of reacting with either component (A) or component (B). The reactive group is selected from (meth)acryloyl, alkenyl, and hydrosilyl, i.e., SiH group. The content of the (D) polysiloxane compound is 0.1 to 30 parts by mass relative to the total of 100 parts by mass of component (A), component (B) and (D) polysiloxane compound.

2. The two-component thermally conductive composition according to claim 1, wherein the reactive group is (meth)acryloyl.

3. The two-component thermally conductive composition according to claim 1 or 2, wherein the (D) polysiloxane compound has one reactive group.

4. The two-component thermally conductive composition according to claim 1 or 2, wherein the alkyl group of the (D) polysiloxane compound is butyl.

5. The two-component thermally conductive composition according to claim 1 or 2, wherein the (D) polysiloxane compound is a compound represented by formula (1). X is an organic group with a reactive group; at least one of B, C, and D is a group shown in formula (2) below, and the rest are methyl or phenyl; when there are multiple groups shown in formula (2), the multiple groups shown in formula (2) can be the same or different; R1 and R2 are each independently methyl or phenyl; at least one of R3, R4, and R5 is an alkyl group with 4 or more carbon atoms, and the others are each independently methyl, phenyl, or X; * refers to the bonding bond with Si of formula (1); n is an integer from 9 to 130.

6. The two-component thermally conductive composition according to claim 1 or 2, wherein the alkenyl group in component (A) is an alkenyl group having 2 to 8 carbon atoms.

7. The two-component thermally conductive composition according to claim 1 or 2, wherein component (B) comprises a hydrogenated organopolysiloxane with a hydrogenated silane content of 2 mmol / g or more.

8. The two-component thermally conductive composition according to claim 1 or 2, wherein component (A) and component (B) are in a liquid state.

9. The two-component thermally conductive composition according to claim 1 or 2, wherein the thermally conductive filler material (C) is at least one selected from metals, metal oxides, metal nitrides, metal hydroxides, carbon materials, oxides other than metals, nitrides other than metals, and carbides other than metals.

10. The two-component thermally conductive composition according to claim 1 or 2, wherein the average particle size of the thermally conductive filler material (C) is 0.1 to 200 μm.

11. The two-component thermally conductive composition according to claim 1 or 2, wherein the thermally conductive filler material (C) is used in combination with a small-particle-size thermally conductive filler material with an average particle size of 0.1 μm or more and 5 μm or less, and a large-particle-size thermally conductive filler material with an average particle size of more than 5 μm and 200 μm or less.

12. The two-component thermally conductive composition according to claim 1 or 2, wherein the content of the thermally conductive filler material (C) is 150 to 3000 parts by mass relative to a total of 100 parts by mass of component (A), component (B), and polysiloxane compound (D).

13. The two-component thermally conductive composition according to claim 1 or 2, wherein the second agent further comprises (A) an organopolysiloxane having at least two alkenyl groups.

14. The two-component thermally conductive composition according to claim 1 or 2, wherein the mass ratio of the second agent to the first agent, i.e., the second agent / first agent, is 0.9 to 1.

1.

15. The two-component thermally conductive composition according to claim 1 or 2, wherein the viscosity ratio of the second agent to the first agent, i.e., the second agent / first agent ratio, is 0.5 to 2.

0.

16. A thermally conductive component, which is formed by curing the two-component thermally conductive composition according to any one of claims 1 to 15.

17. The thermally conductive component according to claim 16, wherein its E hardness is 30 to 90.

18. The thermally conductive component according to claim 16 or 17, wherein the thermal conductivity is 1.0 W / m. K and above.

19. A battery module comprising a gap material made of a thermally conductive member as described in any one of claims 16 to 18, a plurality of battery cells, and a module housing for storing the plurality of battery cells, wherein the gap material is disposed inside the module housing.

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