Thermally conductive member, method for manufacturing the thermally conductive member, and battery module

Abstract

To provide a thermally conductive member that satisfies both thermal conductivity and insulation properties.SOLUTION: A thermally conductive member contains matrix resin and fillers, where the fillers include rod-like or flaky first fillers and rod-like or flaky second fillers, the volume resistivity of the first fillers is 1012 Ωcm or more, the magnetic susceptibility of the first fillers is 10-6 or less, the magnetic susceptibility of the second fillers is 10-5 or more, the content of the first fillers is larger than the content of the second fillers, and in the case where the thermally conductive member is viewed in a cross-section, and the fillers in which the angle of the fillers in the longitudinal direction for a thickness direction of the thermally conductive member is ±30° or less are fillers X, a ratio of the fillers X for all of the fillers is 30% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a thermally conductive member, a method for manufacturing a thermally conductive member, and a battery module. [Background technology]

[0002] A technique for dissipating heat generated from a heat-generating body using a heat sink is known. For example, in electronic devices such as computers, heat sinks and other heat sinks are used to dissipate heat generated from heat-generating bodies such as semiconductor devices. To improve the efficiency of heat transfer from the heat-generating body to the heat sink, a thermally conductive member may be disposed between the heat-generating body and the heat sink.

[0003] Patent Document 1 discloses a thermally conductive molded body in which boron nitride powder is magnetically oriented in a specific direction in a polymer. Patent Document 2 discloses a thermally conductive resin molded body containing, as a thermally conductive filler, thermally conductive particles with a high magnetic field response and thermally conductive particles with a low magnetic field response, with the thermally conductive particles with a high magnetic field response being oriented in the thickness direction of the molded body. Patent Document 3 discloses a sheet-like heat dissipation member containing a thermally conductive filler including an agglomerated powder of hexagonal boron nitride having a predetermined orientation index and aluminum oxide powder, and a silicone resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-172398 [Patent Document 2] Patent Publication No. 2021-038353 [Patent Document 3] International Publication No. 2019-031458 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, electronic devices have a high heat density and are often used under high voltages, making it important to ensure heat dissipation and insulation. For example, batteries also generate heat during charging and discharging and are used under high voltages, making it important to ensure heat dissipation and insulation. Heat sinks are often made of highly conductive (low insulating) materials such as metals, and the thermally conductive member placed between the heat sink and the heat source must have good thermal conductivity as well as good insulation. As will be discussed in more detail later, attempts to improve thermal conductivity can sometimes result in insufficient insulation, making it difficult to achieve both thermal conductivity and insulation.

[0006] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a thermally conductive member that has both thermal conductivity and electrical insulation properties. [Means for solving the problem]

[0007] [1] A thermally conductive member containing a matrix resin and a filler, The filler includes a rod-shaped or flake-shaped first filler and a rod-shaped or flake-shaped second filler, The volume resistivity of the first filler is 10 12 Ωcm or more, The magnetic susceptibility of the first filler is 10 -6 is as follows: The magnetic susceptibility of the second filler is 10 -5 That's all, The content of the first filler is greater than the content of the second filler, A thermally conductive member, wherein, when the filler X is defined as a filler having an angle of ±30° or less between the longitudinal direction of the filler and the thickness direction of the thermally conductive member in a cross-sectional view of the thermally conductive member, the proportion of the filler X to all the fillers is 30% or more.

[0008] [2] The thermal conductive member according to [1], wherein the thermal conductive member has a breakdown voltage of 5 kV / mm or more in the thickness direction.

[0009] [3] The thermally conductive member according to [1] or [2], wherein the thermal conductivity of the thermally conductive member in the thickness direction is 2.03 W / mK or more.

[0010] [4] The thermally conductive member according to any one of [1] to [3], wherein the proportion of the filler relative to the total of the matrix resin and the filler is 20 mass % or more and less than 50 mass %.

[0011] [5] The thermally conductive member according to any one of [1] to [4], wherein the ratio of the filler to the total of the matrix resin and the filler is 10% by volume or more and 40% by volume or less.

[0012] [6] The thermally conductive member according to any one of [1] to [5], wherein the proportion of the filler X to all the fillers is 50% or more.

[0013] [7] The thermally conductive member according to any one of [1] to [6], wherein the proportion of the filler X to all the fillers is 70% or more.

[0014] [8] The volume resistivity of the matrix resin is 10 12 The thermally conductive member according to any one of [1] to [7], having a resistivity of Ωcm or more.

[0015] [9] The volume resistivity of the second filler is 10 -2 The thermal conductive member according to any one of [1] to [8], having a resistivity of Ωcm or less.

[0016]

[10] The thermally conductive member according to any one of [1] to [9], wherein the matrix resin is a cured product of a curable resin.

[0017]

[11] The thermally conductive member according to

[10] , wherein the curable resin is a thermosetting resin.

[0018]

[12] The thermally conductive member according to

[11] , wherein the thermosetting resin is a silicone resin or an epoxy resin.

[0019]

[13] The thermally conductive member according to any one of [1] to

[12] , wherein the first filler is flake-shaped and the second filler is rod-shaped.

[0020]

[14] The thermally conductive member according to any one of [1] to

[13] , wherein the material of the first filler is boron nitride, aluminum nitride, silicon nitride, beryllia, magnesia, or alumina.

[0021]

[15] The thermally conductive member according to any one of [1] to

[14] , wherein the material of the second filler is carbon, metal, or metal oxide.

[0022]

[16] The thermally conductive member according to any one of [1] to

[15] , which is used in a battery module.

[0023]

[17] A method for producing a thermally conductive member according to any one of [1] to

[16] , a precursor layer forming step of forming a precursor layer using a resin composition containing a curable resin for forming the matrix resin and the filler; a curing step of applying a magnetic field to the precursor layer in the thickness direction to orient the filler in the precursor layer while curing the curable resin; A method for manufacturing a thermally conductive member comprising the steps of:

[0024]

[18] The method for producing a thermally conductive member according to

[17] , wherein the viscosity of the curable resin is 1 Pa·s or less.

[0025]

[19] A battery module having a battery and a heat dissipation member, A battery module, wherein the thermally conductive member according to any one of [1] to

[16] is disposed between the battery and the heat dissipation member. [Effects of the Invention]

[0026] The thermally conductive member according to the present disclosure has the advantage of being able to achieve both thermal conductivity and electrical insulation. [Brief explanation of the drawings]

[0027] [Figure 1] 1A and 1B are a schematic cross-sectional view illustrating a thermally conductive member according to the present disclosure and a schematic perspective view enlarging a portion of the thermally conductive member according to the present disclosure; [Figure 2] FIG. 2 is an explanatory diagram illustrating a filler X in the present disclosure. [Figure 3] 1A and 1B are a schematic perspective view and a schematic plan view illustrating the shape of a filler in the present disclosure. [Figure 4] 1A and 1B are schematic side views and schematic plan views illustrating the shape of a filler in the present disclosure. [Figure 5] FIG. 1 is a flow diagram illustrating a method for manufacturing a thermally conductive member according to the present disclosure. [Figure 6] 1 is a schematic perspective view illustrating a battery module according to the present disclosure. [Figure 7] 10A-10C are binarized images and histograms illustrating results of embodiments in the present disclosure. [Figure 8] 10 is a binarized image and histogram illustrating the results of a comparative example in the present disclosure. [Figure 9] 1 is a graph showing the relationship between the amount of filler and thermal conductivity in Examples 1 to 4 and Comparative Examples 1 to 10. DETAILED DESCRIPTION OF THE INVENTION

[0028] The thermally conductive member, the method for manufacturing the thermally conductive member, and the battery module according to the present disclosure will be described in detail below with reference to the drawings. The drawings are schematic, and the size and shape of each part are appropriately exaggerated for ease of understanding.

[0029] A. Thermally conductive materials FIG. 1(a) is a schematic cross-sectional view illustrating a thermally conductive member according to the present disclosure, and FIG. 1(b) is a schematic perspective view enlarging a portion of the thermally conductive member according to the present disclosure. As shown in FIG. 1(a), the thermally conductive member 10 is, for example, in the form of a sheet. As shown in FIG. 1(b), the thermally conductive member 10 contains a matrix resin 1 and a filler F. The filler F further contains rod-shaped or flake-shaped first filler 2 and rod-shaped or flake-shaped second filler 3. The volume resistivity of the first filler 2 is 10 12 The magnetic susceptibility of the first filler 2 is 10 -6 The magnetic susceptibility of the second filler 3 is 10 -5 That is, the second filler 3 has a higher magnetic susceptibility and a higher magnetic field response than the first filler 2. The content of the first filler 2 is greater than the content of the second filler 3.

[0030] As shown in FIG. 1( a) and FIG. 2, the thermally conductive member 10 is viewed in cross section, and the longitudinal direction of the filler F is D. L The thickness direction D of the thermal conductive member 10 T The longitudinal direction D of the filler F L The filler F for which the angle is ±30° or less is referred to as “filler X.” In the present disclosure, the proportion of filler X to all fillers F contained in thermally conductive member 10 is 30% or more.

[0031] According to the present disclosure, a thermally conductive member that combines thermal conductivity and insulation properties is obtained by using a first filler and a second filler that have different magnetic susceptibilities and by having the proportion of filler X fall within a specific range. As described above, modern electronic devices have high heat generation densities and are often used under high voltages, making it important to ensure heat dissipation and insulation properties. Furthermore, for example, batteries also generate heat during charging and discharging and are used under high voltages, making it important to ensure heat dissipation and insulation properties. Heat sinks often use materials with high conductivity (low insulation properties), such as metals, and the thermally conductive member disposed between the heat sink and the heat sink is required to have good insulation properties in addition to good thermal conductivity.

[0032] For example, the boron nitride described in Patent Document 1 is a material with good thermal conductivity and electrical insulation, but is a flaky (scale-like) powder and is known to have anisotropic thermal conductivity. Specifically, the thermal conductivity in the thickness direction is significantly different from the thermal conductivity in the in-plane direction (the direction perpendicular to the thickness direction), with the latter being significantly greater. Therefore, in order to achieve good thermal conductivity in the thickness direction of a thermally conductive member, it is necessary to orient the boron nitride along the thickness direction of the thermally conductive member. For example, Patent Document 1 discloses that boron nitride is oriented by applying a magnetic field to it. However, because boron nitride has a low magnetic field response (low magnetic susceptibility), it is difficult to orient the boron nitride along the thickness direction of the thermally conductive member, and there is room for improvement in thermal conductivity.

[0033] On the other hand, Patent Document 2 discloses the combined use of thermally conductive particles with high magnetic field responsiveness and thermally conductive particles with low magnetic field responsiveness. Furthermore, Patent Document 2 discloses the use of nickel-plated graphite as the thermally conductive particles with high magnetic field responsiveness, and that it is preferable that the content of the thermally conductive particles with high magnetic field responsiveness be greater than the content of the thermally conductive particles with low magnetic field responsiveness. Nickel-plated graphite has high electrical conductivity, making it difficult to achieve good insulating properties.

[0034] Patent Document 3 discloses a sheet-like heat dissipation member containing a thermally conductive filler including an agglomerated powder of hexagonal boron nitride having a predetermined orientation index and aluminum oxide powder, and a silicone resin. Because boron nitride and aluminum oxide have low magnetic field response (low magnetic susceptibility), it is difficult to orient the boron nitride along the thickness direction of the thermally conductive member, and there is room for improvement in thermal conductivity.

[0035] In contrast, in the present disclosure, by using a second filler with high magnetic field responsiveness in addition to a first filler with low magnetic field responsiveness, the second filler acts as a driving force for orienting the first filler. This makes it easier to orient the rod-shaped or flake-shaped first filler along the thickness direction of the thermally conductive member, further improving thermal conductivity. Furthermore, because the first filler has high volume resistivity and the content of the first filler is greater than the content of the second filler, good insulation can be ensured, even if the second filler is conductive. Therefore, high levels of thermal conductivity and insulation can be achieved.

[0036] 1. Filler The filler in the present disclosure includes a rod-shaped or flake-shaped first filler and a rod-shaped or flake-shaped second filler. In the present disclosure, "rod-shaped" includes shapes called fiber-shaped or needle-shaped, and "flake-shaped" includes shapes called scale-shaped, thin plate-shaped, or plate-shaped.

[0037] FIG. 3(a) is a schematic perspective view illustrating a rod-shaped filler, and FIG. 3(b) is a schematic plan view illustrating a rod-shaped filler. Rod-shaped filler F usually has an elongated shape. Rod-shaped filler F has a shape in which the length in the extension direction (the y-axis direction in FIG. 3) is the longest part. In addition, in FIGS. 3(a) and 3(b), the outer edge shape of the filler when cut along a plane (xz plane) whose normal direction is the extension direction (y-axis direction) is a perfect circle. However, the outer edge shape may be a shape other than a perfect circle. Shapes other than a perfect circle are not particularly limited, and examples thereof include ellipses and polygons such as rectangles.

[0038] FIG. 4(a) is a schematic side view illustrating a flake-shaped filler, and FIG. 4(b) is a schematic plan view illustrating a flake-shaped filler. Flake-shaped filler F usually has a thin shape. Flake-shaped filler F has a shape in which the length in the extension direction (thickness direction, normal direction to the main surface, z-axis direction in FIG. 4) is the shortest part. In addition, in FIG. 4(b), the outer edge shape of the filler when viewed from the thickness direction (z-axis direction) is elliptical. However, the outer edge shape may be a shape other than an ellipse. Shapes other than an ellipse are not particularly limited, and examples thereof include perfect circles and polygons such as rectangles.

[0039] In the filler, the length of the longest part is defined as "length a" and the length of the shortest part is defined as "length b." As shown in FIG. 3(b), in the case of rod-shaped filler F, the length in the extension direction (longitudinal direction, y-axis direction) usually corresponds to "length a," and the length in the radial direction perpendicular to the extension direction corresponds to "length b." On the other hand, as shown in FIG. 4(b), in the case of flake-shaped filler F, the length in the extension direction (thickness direction, z-axis direction) usually corresponds to "length b," and the length in the longitudinal direction of filler F as viewed from the thickness direction corresponds to "length a." Also, as shown in FIG. 4(b), in the case of flake-shaped filler F, the length in the direction perpendicular to the longitudinal direction of filler F as viewed from the thickness direction (z-axis direction) is defined as "length c." Lengths a, b, and c can be determined by observation using an electron microscope or CT inspection device. It is preferable to use 100 or more samples for observation.

[0040] As shown in Figures 3(a) and 3(b), in the case of rod-shaped filler F, the ratio of length a to length b (a / b) is usually greater than 1, and may be 1.2 or greater, or even 1.5 or greater. On the other hand, a / b is, for example, 15 or less, or may be 10 or less. Length a is not particularly limited, but may be, for example, 30 µm or more and 100 µm or less, or 40 µm or more and 80 µm or less. On the other hand, length b is not particularly limited, but may be, for example, 3 µm or more and 30 µm or less, or 5 µm or more and 20 µm or less.

[0041] As shown in FIGS. 4(a) and 4(b), in the case of flake-shaped filler F, the ratio of length a to length b (a / b) is typically greater than 1, and may be 5 or greater, or 10 or greater. Meanwhile, a / b may be, for example, 100 or less, or 70 or less. Length a is not particularly limited, but may be, for example, 15 μm or more and 200 μm or less, or 20 μm or more and 150 μm or less. Meanwhile, length b is not particularly limited, but may be, for example, 0.5 μm or more and 20 μm or less, or 1 μm or more and 10 μm or less. Furthermore, the ratio of length c to length b (c / b) is typically greater than 1, and may be 5 or more, or 10 or more. Meanwhile, c / b may be, for example, 100 or less, or 70 or less. Meanwhile, length c is not particularly limited, but may be, for example, 15 μm or more and 200 μm or less, or 20 μm or more and 150 μm or less. The ratio of the length a to the length c (a / c) is usually greater than 1 and may be 1.2 or greater. On the other hand, a / c is, for example, 5 or less.

[0042] (1) First filler The thermally conductive member of the present disclosure contains a first filler. The first filler preferably has a high volume resistivity (volume resistivity). In other words, the first filler preferably has high insulating properties. This is because a thermally conductive member with good insulating properties can be obtained. The volume resistivity of the first filler is usually 10 12 Ωcm or more, 10 13 It may be 10 Ωcm or more. 14 The volume resistivity may be Ωcm or more. The volume resistivity can be determined by a constant voltage application method.

[0043] The first filler preferably has low magnetic susceptibility. In other words, the first filler preferably has low magnetic field response. In the present disclosure, magnetic susceptibility refers to volume magnetic susceptibility (SI unit system). The magnetic susceptibility of the first filler is usually 10 -6 is less than or equal to 10 -7 The first filler may have a magnetic susceptibility of 10 or less. -6The magnetic susceptibility may be a paramagnetic material having a positive value or a diamagnetic material having a negative value.

[0044] The first filler preferably has high thermal conductivity. By using a first filler with high thermal conductivity, a thermally conductive member with good thermal conductivity can be obtained. Furthermore, the first filler usually has higher thermal conductivity than the matrix resin. The thermal conductivity of the first filler is, for example, 20 W / mK or more, or may be 50 W / mK or more, or may be 100 W / mK or more. The thermal conductivity of the first filler is, for example, 300 W / mK or less.

[0045] The first filler is preferably an inorganic filler, and examples of the material for the first filler include boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), beryllia (BeO), magnesia (MgO), and alumina (Al2O3). Among these, boron nitride (BN) is preferred, and hexagonal boron nitride (h-BN) is particularly preferred.

[0046] [Table 1]

[0047] When the above-mentioned "ratio of length a to length b (a / b)" is defined as the aspect ratio, the aspect ratio of the first filler may be larger than the aspect ratio of the second filler, because this makes it easier for the first filler to be oriented.

[0048] The content of the first filler in the thermally conductive member is, for example, 25 parts by mass or more and 90 parts by mass or less, or may be 30 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the matrix resin. In the present disclosure, the content of the first filler is typically greater than the content of the second filler. The proportion of the first filler relative to the total of the first filler and the second filler is, for example, 85% by mass or more, or may be 90% by mass or more, or may be 95% by mass or more.

[0049] (2) Second filler The thermally conductive member according to the present disclosure contains a second filler. The second filler has a higher magnetic susceptibility than the first filler. That is, the second filler has a higher magnetic field response than the first filler. The magnetic susceptibility of the second filler is typically 10 -4 That's it, 10 -3 On the other hand, the magnetic susceptibility of the second filler may be, for example, 10 6 The second filler has a magnetic susceptibility of 10 -4 Over 10 -3 It may be a paramagnetic substance with a magnetic susceptibility of 10 or less. 2 It may be a ferromagnetic material with a magnetic susceptibility of 100 .mu.m or more, or a diamagnetic material with a negative magnetic susceptibility.

[0050] The volume resistivity of the second filler is not particularly limited. -2 It may be a conductor having a volume resistivity of 10 Ωcm or less. -2 Ωcm or more and 10 4 It may be a semiconductor having a volume resistivity of less than 10 4 The volume resistivity can be determined by a constant current application method or a constant voltage application method.

[0051] The second filler preferably has high thermal conductivity. By using a second filler with high thermal conductivity, a thermally conductive member with high thermal conductivity can be obtained. Furthermore, the second filler usually has higher thermal conductivity than the matrix resin. The second filler preferably has a higher thermal conductivity than the first filler.

[0052] The second filler is preferably an inorganic filler. Examples of materials for the second filler include carbon, metals, or metal oxides. Examples of metals include nickel, iron, and cobalt. Examples of metal oxides include iron oxide, chromium oxide, and ferrite. Specific examples of the second filler include carbon fiber, metal fiber, and metal oxide fiber. For example, when the second filler is rod-shaped, the second filler may have a rod-shaped substrate and a coating layer that covers the surface of the substrate. Examples of rod-shaped substrates include carbon fiber, metal fiber, and resin fiber. The coating layer preferably contains the above-mentioned carbon, metal, or metal oxide. Specific examples of such second fillers include fillers that have carbon fiber and a nickel layer that covers the surface of the carbon fiber.

[0053] The content of the second filler in the thermally conductive member is, for example, 0.2 parts by mass or more and 15 parts by mass or less, and may be 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the matrix resin.

[0054] (3) Filler The thermally conductive member according to the present disclosure typically contains a first filler and a second filler as the main filler components. The thermally conductive member may contain only the first filler and the second filler, or may contain another filler in addition to the first filler and the second filler. The total proportion of the first filler and the second filler relative to all fillers contained in the thermally conductive member is typically 50% by mass or more, or may be 70% by mass or more, or may be 90% by mass or more.

[0055] The proportion of the filler relative to the total of the matrix resin and the filler may be, for example, 20% by mass or more and less than 50% by mass, or 25% by mass or more and 45% by mass or less, or 10% by volume or more and 40% by volume or less, or 15% by volume or more and 35% by volume or less.

[0056] (4) Filler X ratio As shown in FIG. 1( a) and FIG. 2, the thermally conductive member 10 is viewed in cross section, and the longitudinal direction of the filler F is D. L The thickness direction D of the thermal conductive member 10 T The longitudinal direction D of the filler F L Filler F for which the angle is ±30° or less is referred to as "filler X." In the present disclosure, the proportion of filler X to all fillers F contained in thermally conductive member 10 is 30% or more. The proportion of filler X may be 50% or more, 65% or more, 70% or more, 75% or more, or 80% or more. As the proportion of filler X increases, thermal conductivity is further improved.

[0057] 2. Matrix resin The thermally conductive member according to the present disclosure contains a matrix resin. The matrix resin preferably has high volume resistivity. That is, the matrix resin preferably has high insulating properties. The volume resistivity of the matrix resin is, for example, 10 12 Ωcm or more, 10 13 It may be 10 Ωcm or more. 14 The volume resistivity may be Ωcm or more. The volume resistivity can be determined by a constant voltage application method.

[0058] The matrix resin usually has a low magnetic susceptibility. For example, the magnetic susceptibility of the matrix resin is 10 -6 is less than or equal to 10 -7 The matrix resin usually has a lower thermal conductivity than the filler. The thermal conductivity of the matrix resin is, for example, 1 W / mK or less, and may be 0.5 W / mK or less.

[0059] The matrix resin is preferably a cured product of a curable resin. The curable resin may be a thermosetting resin or an ionizing radiation-curable resin. Examples of thermosetting resins include silicone resins and epoxy resins. Examples of silicone resins include straight silicone resins such as methylsilicone resin, methylphenylsilicone resin, and phenylsilicone resin; and organic resin-modified silicone resins such as alkyd-modified silicone resin, polyester-modified silicone resin, urethane-modified silicone resin, epoxy-modified silicone resin, and acrylic-modified silicone resin. Examples of curing agents for curing silicone resins include room-temperature curing agents such as organic titanate-based curing agents; catalyst-type curing agents such as zinc dioctoate; and reactive curing agents such as silane coupling agents.

[0060] Examples of epoxy resins include bisphenol A epoxy resins, novolac epoxy resins, alicyclic epoxy resins, long-chain aliphatic epoxy resins, glycidyl ester epoxy resins, and glycidyl amine epoxy resins. Examples of curing agents for curing epoxy resins include amine-based curing agents, acid anhydride-based curing agents, and polyamide curing agents. Thermosetting resins may be either one-component curing types or two-component curing types.

[0061] The content of the matrix resin in the thermally conductive member is, for example, 50% by mass or more and 85% by mass or less, and may be 60% by mass or more and 80% by mass or less.

[0062] 3. Thermally conductive materials The thermally conductive member according to the present disclosure contains a matrix resin and a filler. Details of the matrix resin and the filler are as described above. The thermally conductive member preferably has a high breakdown voltage in the thickness direction. Specifically, the breakdown voltage of the thermally conductive member in the thickness direction is preferably 5 kV / mm or more. The thermally conductive member also preferably has a high thermal conductivity in the thickness direction. Specifically, the thermal conductivity of the thermally conductive member in the thickness direction is, for example, 2.03 W / mK or more, or may be 2.36 W / mK or more, or may be 3.14 W / mK or more.

[0063] The shape of the thermally conductive member is not particularly limited, but examples thereof include a sheet shape. The term "sheet shape" includes shapes known as film shapes or plate shapes. The thermally conductive member may have any three-dimensional shape. The uses of the thermally conductive member are not particularly limited, but examples thereof include battery modules; electronic components such as LEDs and home appliances; and information and communication modules such as optical communication devices.

[0064] B. Manufacturing method of thermally conductive member 5 is a flow diagram illustrating a method for manufacturing a thermally conductive member according to the present disclosure. As shown in FIG. 5, a precursor layer is formed using a resin composition containing a curable resin for forming a matrix resin and a filler (precursor layer forming step). Next, a magnetic field is applied to the precursor layer in the thickness direction to orient the filler in the precursor layer and cure the curable resin (curing step).

[0065] According to the present disclosure, a thermally conductive member that has both thermal conductivity and electrical insulation properties can be obtained by using a first filler and a second filler that have different magnetic susceptibilities and curing a curable resin while applying a magnetic field.

[0066] 1. Precursor layer formation process The precursor layer forming step in the present disclosure is a step of forming a precursor layer using a resin composition containing a curable resin for forming a matrix resin and a filler.

[0067] The resin composition contains a first filler and a second filler as fillers. The resin composition may also contain a curing agent that cures the curable resin. Details of the curable resin, filler, and curing agent are the same as those described above in "A. Thermally conductive member." The viscosity of the curable resin is preferably, for example, 1 Pa·s or less. This is because, when the curable resin is cured, the filler is likely to be oriented along the applied magnetic field. Examples of methods for forming the precursor layer include a method of coating the resin composition on a substrate. The type of substrate is not particularly limited, but examples include heat dissipation members.

[0068] 2.Curing process The curing step in the present disclosure is a step of applying a magnetic field to the precursor layer in the thickness direction to orient the filler in the precursor layer while curing the curable resin.

[0069] A magnetic field is applied to the precursor layer in the thickness direction. This causes the rod-shaped or flake-shaped filler to be oriented along the thickness direction. The magnetic flux density of the applied magnetic field is not particularly limited, but is, for example, 0.5 T or more and 10 T or less. When the curable resin is a thermosetting resin, the thermosetting resin may be cured at room temperature or by heating. On the other hand, when the curable resin is an ionizing radiation curable resin, the ionizing radiation curable resin is cured by irradiating it with ionizing radiation (e.g., ultraviolet light).

[0070] 3. Thermally conductive materials The thermally conductive member obtained by the above-described steps is the same as that described above in "A. Thermally conductive member," and therefore will not be described here.

[0071] C. Battery module Fig. 6(a) is a schematic perspective view illustrating a battery module according to the present disclosure, and Fig. 6(b) is an exploded view of Fig. 6(a). The battery module 40 shown in Figs. 6(a) and 6(b) includes a battery 20, a heat dissipation member 30, and a thermally conductive member 10 disposed between the battery 20 and the heat dissipation member 30.

[0072] According to the present disclosure, by disposing the above-described thermally conductive member between the battery and the heat dissipation member, a battery module with good heat dissipation and insulation properties can be obtained.

[0073] 1.Battery A battery in the present disclosure typically has at least one cell. The cell typically has a power generating element and an exterior body that covers the power generating element. The power generating element typically has at least one power generating unit that has a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode. The battery 20 shown in Figures 6(a) and (b) has multiple cells C arranged in one direction.

[0074] 2. Heat dissipation materials The heat dissipation member in the present disclosure is a member that receives heat generated by a chemical reaction in the battery and dissipates the heat to another medium. The type of heat dissipation member is not particularly limited, and any known heat dissipation member (e.g., a cooling member) can be used.

[0075] 3. Thermally conductive materials The thermally conductive member in the present disclosure is disposed between the battery and the heat dissipation member. The thermally conductive member is the same as that described above in "A. Thermally conductive member."

[0076] 4. Battery module Examples of applications of the battery module of the present disclosure include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, it is preferable to use the battery module as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery module of the present disclosure may also be used as a power source for mobile objects other than vehicles (e.g., trains, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0077] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0078] [Example 1] As a thermosetting resin, a room temperature curing silicone resin (viscosity: 650 mPa·s, volume resistivity: 10 14 Ωcm~10 16 As the first filler, boron nitride (manufactured by Momentive) was prepared, and as the second filler, carbon fiber (manufactured by Mitsubishi Chemical Corporation) was prepared. Details of the first filler and the second filler are as follows.

[0079] [Table 2]

[0080] 75 parts by mass of thermosetting resin, 24 parts by mass of first filler, and 1 part by mass of second filler were weighed out and mixed and stirred using a planetary mixer. The resulting composition was poured into a curing container (10 mm thick) and left to stand at room temperature for 90 minutes while applying a magnetic field with a magnetic flux density of 8 T from both the top and bottom surfaces in the thickness direction using a magnetic field molding device equipped with a pulse magnetizing coil, thereby curing the thermosetting resin. This resulted in a sheet-shaped thermally conductive member.

[0081] [Examples 2 to 4 and Comparative Examples 1 to 3] A thermally conductive member was obtained in the same manner as in Example 1, except that the blending amounts of the thermosetting resin, the first filler, and the second filler were changed as shown in Table 3.

[0082] [Comparative Examples 4 to 11] A thermally conductive member was obtained in the same manner as in Example 1, except that the amounts of the thermosetting resin, the first filler, and the second filler were changed as shown in Table 4 and no magnetic field was applied.

[0083] [evaluation] (Filler X ratio) The proportion of filler X in the thermally conductive members obtained in Examples 1 to 4 and Comparative Examples 1 to 11 was measured. Specifically, cross-sectional images were created using a CT scanner, binarized, and the angles of the fillers in the binarized images were measured to create histograms. The results are shown in Tables 3 and 4. FIG. 7(a) is a binarized image of the cross section of the thermally conductive member obtained in Example 3, and FIG. 7(b) is a histogram in which the fillers in FIG. 7(a) are classified by the angle of the longitudinal direction of the fillers relative to the thickness direction of the thermally conductive member. Similarly, FIG. 8(a) is a binarized image of the cross section of the thermally conductive member obtained in Comparative Example 9, and FIG. 8(b) is a histogram in which the fillers in FIG. 8(a) are classified by the angle of the longitudinal direction of the fillers relative to the thickness direction of the thermally conductive member. As shown in FIGS. 7(a) and 7(b), when a magnetic field was applied, the proportion of filler X was as high as 84%. In contrast, as shown in FIGS. 8(a) and 8(b), when no magnetic field was applied, the proportion of filler X was as low as 23%.

[0084] (Measurement of thermal conductivity) The thermal conductivity of the thermally conductive members obtained in Examples 1 to 4 and Comparative Examples 1 to 11 was measured. Specifically, the thermal conductivity of the thermally conductive members was measured by a steady-state method (heat flow meter method). The results are shown in Tables 3 and 4.

[0085] (Measurement of breakdown voltage) The breakdown voltage (BDV) of the thermally conductive members obtained in Examples 1 to 4 and Comparative Examples 1 to 11 was measured. Specifically, the breakdown voltage was calculated based on IEC 60243-1 by dividing the voltage at which breakdown occurred by the thickness of the thermally conductive member. The results are shown in Tables 3 and 4.

[0086] [Table 3]

[0087] [Table 4]

[0088] FIG. 9 is a graph showing the relationship between the filler amount and thermal conductivity in Examples 1 to 4 and Comparative Examples 1 to 10. As shown in FIG. 9, Tables 3 and 4, Comparative Examples 4 to 6 used a first filler but no second filler, and no magnetic field was applied during curing of the thermosetting resin. As a result, the filler was not oriented in the thickness direction, and the thermal conductivity in the thickness direction was low. Furthermore, in Comparative Examples 4 to 6, increasing the filler amount did not improve the thermal conductivity. Furthermore, in Comparative Examples 4 to 6, the breakdown voltage was high and good insulation properties were obtained.

[0089] In Comparative Examples 7 to 10, both a first filler and a second filler were used, but a magnetic field was not applied during the curing of the thermosetting resin, so the fillers were not oriented in the thickness direction, resulting in low thermal conductivity in the thickness direction. Furthermore, in Comparative Examples 7 to 10, increasing the amount of filler did not improve thermal conductivity. In Comparative Example 10, a decrease in breakdown voltage was observed. This is presumably due to the excessive proportion of the second filler, which has high electrical conductivity. Furthermore, in Comparative Example 11, a second filler was used, but a first filler, which has high thermal conductivity, was not used, and furthermore, a magnetic field was not applied during the curing of the thermosetting resin, resulting in low thermal conductivity. Furthermore, because the second filler has high electrical conductivity, the breakdown voltage was low, and good insulation properties were not obtained.

[0090] In Comparative Examples 1 to 3, the first filler was used but the second filler was not used, but a magnetic field was applied during the curing of the thermosetting resin, so the filler was oriented in the thickness direction, and the thermal conductivity was relatively high. Furthermore, in Comparative Examples 1 to 3, increasing the amount of filler improved the thermal conductivity and also increased the breakdown voltage.

[0091] In Examples 1 to 4, both a first filler and a second filler were used, and a magnetic field was applied during the curing of the thermosetting resin. This caused the fillers to be oriented in the thickness direction, resulting in significantly high thermal conductivity. Comparing Examples 1 to 3 with Comparative Examples 1 to 3, the thermal conductivity in Examples 1 to 3 was higher than that in Comparative Examples 1 to 3. This is presumably because the use of a second filler with high magnetic field responsiveness improved the orientation of the first filler. In other words, it was confirmed that a synergistic effect was achieved by using both a first filler and a second filler. Furthermore, in Examples 1 to 4, increasing the filler amount improved the thermal conductivity and the breakdown voltage. Thus, it was confirmed that a thermally conductive member that combines thermal conductivity and insulation properties could be obtained by using a first filler and a second filler with different magnetic susceptibilities and further setting the proportion of filler X within a specific range. [Explanation of symbols]

[0092] 1...Matrix resin 2...First filler 3...Second filler 10...Thermal conductive member 20...Battery 30...Heat dissipation member 40...Battery module

Claims

1. A thermally conductive member containing a matrix resin and a filler, The filler includes a rod-shaped or flake-shaped first filler and a rod-shaped or flake-shaped second filler, The volume resistivity of the first filler is 10 １２ Ωcm or more, The magnetic susceptibility of the first filler is 10 －６ is as follows: The magnetic susceptibility of the second filler is 10 －５ That's all, The content of the first filler is greater than the content of the second filler, the content of the first filler in the thermally conductive member is 25 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the matrix resin, When the thermal conductive member is viewed in cross section, the filler X is defined as a filler having a longitudinal angle of ±30° or less with respect to a thickness direction of the thermal conductive member, and the proportion of the filler X to all the fillers is 30% or more; A thermally conductive member, wherein the thermally conductive member is configured from a single layer in a direction perpendicular to the thickness direction.

2. A thermally conductive member containing a matrix resin and a filler, The filler includes a rod-shaped or flake-shaped first filler and a rod-shaped or flake-shaped second filler, The volume resistivity of the first filler is 10 １２ Ωcm or more, The second filler has a volume resistivity of 10 −2 Ωcm or less, The magnetic susceptibility of the first filler is 10 －６ is as follows: The magnetic susceptibility of the second filler is 10 －５ That's all, The content of the first filler is greater than the content of the second filler, the content of the first filler in the thermally conductive member is 25 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the matrix resin, the content of the second filler in the thermally conductive member is 0.2 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the matrix resin, a total ratio of the first filler and the second filler to all the fillers contained in the thermal conductive member is 50 mass% or more, A thermally conductive member, wherein, in a cross-sectional view of the thermally conductive member, when a filler X is defined as a filler whose longitudinal direction is at an angle of ±30° or less with respect to a thickness direction of the thermally conductive member, a proportion of the filler X to all the fillers is 30% or more.

3. A thermally conductive member as described in claim 1 or claim 2, wherein the aspect ratio of the first filler is greater than the aspect ratio of the second filler.

4. The thermal conductive member has a breakdown voltage of 5 kV / mm or more in the thickness direction, 3. The thermal conductive member according to claim 1, wherein the thermal conductivity of the thermal conductive member in the thickness direction is 2.03 W / mK or more.

5. 3. The thermally conductive member according to claim 1, wherein a ratio of the filler to the total of the matrix resin and the filler is 20 mass % or more and less than 50 mass %.

6. 3. The thermally conductive member according to claim 1, wherein a ratio of the filler to the total of the matrix resin and the filler is 10% by volume or more and 40% by volume or less.

7. 3. The thermally conductive member according to claim 1, wherein the proportion of the filler X to all the fillers is 50% or more.

8. 3. The thermally conductive member according to claim 1, wherein the proportion of the filler X to all the fillers is 70% or more.

9. The volume resistivity of the matrix resin is 10 １２ Ωcm or more, 3. The thermally conductive member according to claim 1, wherein the second filler has a volume resistivity of 10 −2 Ωcm or less.

10. The thermally conductive member according to claim 1 or 2, wherein the matrix resin is a cured product of a curable resin.

11. The thermally conductive member according to claim 10 , wherein the curable resin is a thermosetting resin.

12. The thermally conductive member according to claim 11 , wherein the thermosetting resin is a silicone resin or an epoxy resin.

13. 3. The thermally conductive member according to claim 1, wherein the first filler is in a flake shape and the second filler is in a rod shape.

14. 3. The thermally conductive member according to claim 1, wherein the material of the first filler is boron nitride, aluminum nitride, silicon nitride, beryllia, magnesia, or alumina.

15. The thermally conductive member according to claim 1 or 2, wherein the material of the second filler is carbon, a metal, or a metal oxide.

16. The thermally conductive member according to claim 1 or 2, which is used in a battery module.

17. A method for manufacturing a thermally conductive member, comprising: the thermally conductive member contains a matrix resin and a filler; The filler includes a rod-shaped or flake-shaped first filler and a rod-shaped or flake-shaped second filler, The first filler has a volume resistivity of 10 12 Ωcm or more, the magnetic susceptibility of the first filler is 10 −6 or less; the magnetic susceptibility of the second filler is 10 −5 or more; The content of the first filler is greater than the content of the second filler, the content of the first filler in the thermally conductive member is 25 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the matrix resin, When the thermal conductive member is viewed in cross section, the filler X is defined as a filler having a longitudinal angle of ±30° or less with respect to a thickness direction of the thermal conductive member, and the proportion of the filler X to all the fillers is 30% or more; The method for manufacturing the thermally conductive member includes: a precursor layer forming step of forming a precursor layer using a resin composition containing a curable resin for forming the matrix resin and the filler; a curing step of applying a magnetic field to the precursor layer in the thickness direction to orient the filler in the precursor layer while curing the curable resin; A method for manufacturing a thermally conductive member comprising the steps of:

18. 18. The method for manufacturing a thermally conductive member according to claim 17, wherein the viscosity of the curable resin is 1 Pa·s or less.

19. A battery module having a battery and a heat dissipation member, A battery module, comprising: the thermally conductive member according to claim 1 or 2 disposed between the battery and the heat dissipation member.

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