Heat conducting structure

Abstract

A heat conducting structure (1) comprises a soft heat conducting member (10) that is a soft member having thermal conductivity. The soft heat conducting member (10) is a member that is capable of maintaining the shape thereof. The soft heat conducting member (10) is filled between a heat dissipating member (2) and a receiving member (3).

Description

Heat Conduction Structure

[0001] The present invention relates to a heat conducting structure.

[0002] For example, in electric vehicles (EVs), in order to extend the driving range, there is a demand for miniaturization and high output of the powertrain in order to improve the efficiency of the powertrain, including the motor, battery, and inverter. Achieving a miniaturized powertrain, high output, or both increases the heat generation density. In response to this increase in heat generation density, for example, Patent Document 1 discloses an adhesive designed to maintain adhesive strength even when immersed in a high-temperature electrolyte solution.

[0003] Japanese Patent Application Laid-Open No. 2018-161895

[0004] In order to cope with this increase in heat density, various materials and substances have been proposed. On the other hand, further improvements in heat dissipation technology are required to cope with the increase in heat density.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a heat conduction structure that can realize good heat dissipation.

[0006] In order to achieve the above object, the heat conduction structure of the present invention is a heat conduction structure for conducting heat from a heat-receiving member to a receiving member, and is provided with a soft heat-conducting member, which is a soft member having thermal conductivity, and the soft heat-conducting member is a member that can maintain its shape, and the soft heat-conducting member is filled between the heat-receiving member and the heat-receiving member.

[0007] In the heat conduction structure according to one aspect of the present invention, the thermal conductivity of the soft thermally conductive member is lower than the thermal conductivity of the heat-dissipating member.

[0008] In the heat conduction structure according to one aspect of the present invention, the soft heat conduction member is a paste-like compound having heat conductivity.

[0009] In the heat conduction structure according to one aspect of the present invention, the soft heat conduction member includes grease and heat conductive particles.

[0010] In the heat conduction structure according to one aspect of the present invention, the receiving member is made of a thermally conductive resin, and the thermal conductivity of the receiving member is lower than the thermal conductivity of the heat-dissipating member.

[0011] In a heat conduction structure according to one embodiment of the present invention, the heat-dissipating member and the receiving member each have a thermal connection portion which is a portion for thermally connecting them to each other, and the soft thermally conductive member is filled between the thermal connection portion of the heat-dissipating member and the thermal connection portion of the receiving member.

[0012] In a heat conduction structure according to one aspect of the present invention, the thermal connection portion of the heat-dissipating member is a protruding portion that protrudes, and the thermal connection portion of the receiving member is a accommodating portion that can accommodate the protruding portion with a gap, and the gap is filled with the soft thermal conductive member.

[0013] In the heat conduction structure according to one aspect of the present invention, the accommodation portion is a recess forming a groove.

[0014] In a heat conduction structure according to one embodiment of the present invention, the thermal connection portion of the heat-dissipating member is a surface, the thermal connection portion of the receiving member is a surface facing the surface of the thermal connection portion of the heat-dissipating member, and the soft thermal conductive member is filled between the surface of the thermal connection portion of the heat-dissipating member and the surface of the thermal connection portion of the receiving member.

[0015] The heat conduction structure according to the present invention can achieve good heat dissipation.

[0016] Fig. 1 is a cross-sectional view showing a schematic configuration of a heat conduction structure according to a first embodiment of the present invention; Fig. 2 is a cross-sectional view showing a schematic configuration of a heat conduction structure according to a second embodiment of the present invention; Fig. 3 is a cross-sectional view showing a schematic configuration of a modified example of the heat conduction structure according to the second embodiment of the present invention; Fig. 4 is a cross-sectional view showing a schematic configuration of an example of the heat conduction structure according to the first embodiment of the present invention; Fig. 5 is a cross-sectional view showing a schematic configuration of an example of the heat conduction structure according to the second embodiment of the present invention.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] The heat conduction structure according to the present invention is a heat conduction structure for conducting heat from a heat-receiving member to a heat-receiving member. The heat-receiving member is a member from which heat is dissipated, and the heat-receiving member is a member that receives heat from the heat-receiving member. The heat-dissipating member is, for example, a member in a device or component that generates heat. The heat-receiving member is, for example, a member in the vicinity of the heat-dissipating member. Figure 1 is a cross-sectional view showing a schematic configuration of a heat conduction structure 1 according to a first embodiment of the present invention.

[0019] As shown in Fig. 1, the heat conduction structure 1 includes a soft heat-conducting member 10, which is a soft member having thermal conductivity. The soft heat-conducting member 10 is a member that can maintain its shape. The soft heat-conducting member 10 is filled between the heat-dissipating member 2 and the receiving member 3. The heat conduction structure 1 will be described in detail below.

[0020] 1, the heat-receiving member 2 and the receiving member 3 have thermal connection portions 20, 30, respectively, which are portions for thermally connecting them to each other. The soft thermally conductive member 10 is filled between the thermal connection portion 20 of the heat-receiving member 2 and the thermal connection portion 30 of the receiving member 3.

[0021] The thermal connection portion 20 of the heat dissipation member 2 is specifically, for example, a protruding portion 21 that is a protruding portion, as shown in Fig. 1. The thermal connection portion 30 of the receiving member 3 is specifically, for example, a housing portion 31 that is a portion that can house the protruding portion 21 with a gap 32, as shown in Fig. 1. The gap 32 between the protruding portion 21 and the housing portion 31 is filled with the soft thermal conductive member 10. The housing portion 31 is, for example, a recess that forms a groove 31a.

[0022] The receiving member 3 is made of, for example, a resin having thermal conductivity (thermal conductive resin). Furthermore, for example, the thermal conductivity of the receiving member 3, that is, the thermal conductivity of the thermal conductive resin that is the material of the receiving member 3, is lower than the thermal conductivity of the heat-dissipating member 2. Specifically, for example, the thermal conductivity of the thermal conductive resin that is the material of the receiving member 3 is lower than the thermal conductivity of the thermal connection portion 20 of the heat-dissipating member 2. Although the thermal conductivity of the thermal conductive resin that makes up the receiving member 3 is thus lower than the thermal conductivity of the heat-dissipating member 2, the thermal conductive resin that makes up the receiving member 3 is, for example, a resin with excellent thermal conductivity and high thermal conductivity.

[0023] The thermally conductive resin used to make the receiving member 3 is a composite material of a resin such as polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polypropylene (PP), or liquid crystal polymer (LCP) and highly thermally conductive particles (fillers). The highly thermally conductive particles may be conductive particles (e.g., conductive fillers) or insulating particles (e.g., insulating fillers). Examples of conductive particle materials include metal and carbon. The conductive particles may be particles made of a single material or a combination of particles made of two or more materials. Specific examples of conductive particles include aluminum particles, copper particles, silver particles, carbon particles, carbon fiber, diamond, and graphite. Examples of insulating particle materials include metal oxides, metal nitrides, metal carbides, and metal hydroxides. The insulating particles may be particles made of a single material or a combination of particles made of two or more materials. Specific examples of thermally conductive particles include aluminum oxide particles, magnesium oxide particles, zinc oxide particles, boron nitride particles, aluminum nitride particles, silicon carbide particles, and aluminum hydroxide particles.

[0024] As shown in FIG. 1 , in the heat conduction structure 1, the protrusion 21 of the heat dissipation member 2 is inserted into the groove 31a of the accommodation portion 31 of the receiving member 3. The protrusion 21 does not contact the groove 31a, but a gap 32 is formed between the groove 31a and the protrusion 21. The groove 31a has, for example, a shape corresponding to the protrusion 21, such that the entire surface of the groove 31a faces the entire surface of the protrusion 21 in the groove 31a. As shown in FIG. 1 , the gap 32 extends between the entire surface of the protrusion 21 in the groove 31a and the entire surface of the groove 31a. As described above, the soft thermal conductive member 10 is filled in the gap 32. Therefore, as shown in FIG. 1 , the soft thermal conductive member 10 contacts the entire surface or substantially the entire surface of the protrusion 21 in the groove 31a and the entire surface or substantially the entire surface of the groove 31a. Note that the soft thermal conductive member 10 does not have to fill the entire gap 32.

[0025] The shape of the groove 31a of the accommodation portion 31 is not limited to a shape corresponding to the above-described protrusion 21. For example, the shape of the groove 31a may be longer than the protrusion 21 in a direction perpendicular to the insertion direction of the protrusion 21. In this case, for example, the soft thermal conductive member 10 does not have to fill the entire groove 31a. Also, for example, the groove 31a may have a shape that makes contact with the protrusion 21 at a portion.

[0026] As described above, the soft thermal conductive member 10 is a soft member that can maintain its shape. Specifically, the soft thermal conductive member 10 is a paste-like member that does not flow, does not deform, or is almost deformed without the action of an external force, at least within the temperature range in which the thermal conductive structure 1 is used, and undergoes plastic deformation when subjected to an external force of a predetermined magnitude. Paste-like materials do not include those that cannot maintain their shape, such as liquids and greases, those that do not form a lump, such as powders, or solids. The soft thermal conductive member 10 is, for example, a paste-like composite material with thermal conductivity. Specifically, the soft thermal conductive member 10 is, for example, a composite material that includes a paste-forming component and a thermally conductive component.

[0027] The soft thermal conductive member 10 is, for example, a compound containing grease and thermally conductive particles. Specifically, the soft thermal conductive member 10 contains, for example, 550 to 800 parts by mass of thermally conductive particles per 100 parts by mass of grease. The thermally conductive particles are, for example, first thermally conductive particles with an average particle size of 30 to 55 μm and second thermally conductive particles with an average particle size of 3 to 15 μm, with the blending ratio of the first thermally conductive particles to the second thermally conductive particles being 7:3 to 5:5 by mass. The soft thermal conductive member 10 also has, for example, a Type OO hardness of 70 or less and an adhesive strength of 10 N or less at 25°C, with a circular area of ​​13 mm in diameter as a unit area.

[0028] The grease of the soft thermal conductive member 10 is a semi-solid or solidified grease in which a thickener is dispersed in a raw base oil. There are no particular limitations on the type of raw base oil or thickener, and any suitable thickener can be used so that the adhesive strength satisfies the above-mentioned numerical range. Examples of raw base oils include mineral oils, synthetic oils, other animal and vegetable oils, and mixtures of these. There are also no particular limitations on the type of thickener, and conventionally known thickeners can be used, such as metal soap-based thickeners such as lithium soap or calcium soap, and non-soap-based thickeners such as silica, urea, PTFE, or bentone.

[0029] The grease of the soft heat conductive member 10 may be a grease containing silicone oil as a raw material base oil, such as silicone grease. An example of silicone grease is "HVG Grease (product name)" manufactured by Toray Dow Corning Co., Ltd. The consistency of the grease is, for example, 100 to 400 immiscible, or 150 to 300. The consistency of the grease can be measured using a consistency meter in accordance with JIS K 2200-2013. For example, a penetration tester "RPM-201" manufactured by Rigo Co., Ltd. can be used as the consistency meter.

[0030] As described above, the soft thermal conductive member 10 contains thermally conductive particles in addition to grease. By including an appropriate amount of such thermally conductive particles, the soft thermal conductive member 10 can be made paste-like, while maintaining low hardness and improving shape retention. Furthermore, the thermal conductivity of the soft thermal conductive member 10 can be adjusted to a desired value. For example, as described above, the amount of thermally conductive particles is 550 to 800 parts by mass, or, for example, 600 to 700 parts by mass, per 100 parts by mass of grease. If the amount of thermally conductive particles is too small, the thermal conductivity and shape retention may decrease, and, for example, the effect of suppressing the adhesiveness of the soft thermal conductive member 10 may be less pronounced. On the other hand, the greater the amount of thermally conductive particles mixed, the higher the thermal conductivity and shape retention of the soft thermal conduction member 10. However, if the amount of thermally conductive particles mixed is too large, the hardness of the soft thermal conduction member 10 increases, the integrity between the grease and the thermally conductive particles decreases, and it may become difficult for the soft thermal conduction member 10 to retain its shape.

[0031] As described above, the soft thermal conductive member 10 is composed of, for example, first thermally conductive particles with an average particle size of 30 to 55 μm and second thermally conductive particles with an average particle size of 3 to 15 μm. By including two types of thermally conductive particle powders with different particle sizes, the soft thermal conductive member 10 is able to pack the thermally conductive particles more tightly within the soft thermal conductive member 10, thereby improving shape retention while maintaining low hardness. By forming the two types of thermally conductive particle powders with different particle sizes into spherical shapes, the thermally conductive particles are able to be closely packed. The particle size of the thermally conductive particles is measured using a laser diffraction particle size distribution measurement method (device: Microtrac).

[0032] As described above, the blending ratio of the first thermally conductive particles to the second thermally conductive particles is 7:3 to 5:5 by mass. Outside this blending ratio range, the packing density of the thermally conductive particles decreases, the hardness of the soft thermally conductive member 10 increases, the integrity of the grease and the thermally conductive particles decreases, and it becomes difficult for the soft thermally conductive member 10 to maintain its shape. The thermally conductive particles may be conductive particles (e.g., conductive filler) or insulating particles (e.g., insulating filler). Examples of conductive particle materials include metal and carbon. They may be particles made of a single material or a combination of particles made of two or more materials. Specific examples of conductive particles include aluminum particles, copper particles, silver particles, carbon particles, carbon fiber, diamond, and graphite.

[0033] When the thermally conductive particles are insulating particles (e.g., insulating fillers), the thermally conductive particles are particles made of at least one material selected from the group consisting of metal oxides, metal nitrides, metal carbides, and metal hydroxides. The thermally conductive particles may be aluminum oxide particles, magnesium oxide particles, zinc oxide particles, boron nitride particles, aluminum nitride particles, silicon carbide particles, or aluminum hydroxide particles. The first thermally conductive particles and the second thermally conductive particles may be particles made of a single material, or may be particles made of a combination of particles made of two or more materials.

[0034] As described above, the average particle size of the first thermally conductive particles is, for example, 30 to 55 μm. The average particle size of the first thermally conductive particles may be 35 to 50 μm, or may be 45 μm. As described above, the average particle size of the second thermally conductive particles is 3 to 15 μm. The average particle size of the second thermally conductive particles may be 4.5 to 9 μm, or may be 5 μm. The average particle sizes of the first thermally conductive particles and the second thermally conductive particles are cumulative average values ​​based on the volume measured by a laser diffraction particle size distribution measurement method (device: Microtrac).

[0035] As described above, the Type OO hardness of the soft thermal conductive member 10 is, for example, 70 or less, but may be 0.5 to 60, or may be 0.5 to 50. The Type OO hardness can be measured using a hardness tester in accordance with ASTM-D 2240-2015. As the hardness tester, for example, a durometer "GSD-754K (product name)" manufactured by Teclock Corporation can be used.

[0036] As described above, the adhesive strength of the soft thermal conductive member 10 at a temperature of 25°C, with a unit area of ​​a circular area 13 mm in diameter, is, for example, 10 N or less, but may be 0.1 to 9 N, or may be 2 to 9 N. The adhesive strength can be measured using a materials testing machine equipped with a rod-shaped probe and a sample pedestal. For example, a compact benchtop testing machine, "EZ-SX (product name)" manufactured by Shimadzu Corporation, can be used as the materials testing machine. The soft thermal conductive member 10 used as the measurement sample is a disk-shaped object with a diameter of 13 mm and a thickness of 1 mm. This measurement sample is placed on the end face of the sample pedestal, and the adhesive strength is measured. The adhesive strength is measured by pressing the probe into the measurement sample placed on the sample pedestal up to a specified compressive load, and then measuring the maximum load [N] when the probe is pulled up. This maximum load [N] is defined as the adhesive strength [N] of the soft thermal conductive member 10 used as the measurement sample. The adhesive strength was measured under the following measurement conditions: a temperature of 25° C., a compression speed of 1 mm / min when the probe was pressed in, a compression load of 5 N, and a pulling speed of 1000 mm / min when the probe was pulled up. The adhesive strength of the soft thermal conductive member 10 measured as described above was 10 N or less.

[0037] As described above, the thermal conductivity of the soft thermal conductive member 10 is lower than the thermal conductivity of the heat-dissipating member 2. The thermal conductivity of the soft thermal conductive member 10 is, for example, 0.4 W / m·K or higher, for example, 2 to 4 W / m·K, or for example, 2 to 3.5 W / m·K. The thermal conductivity of the soft thermal conductive member 10 can be measured using a thermal conductivity measuring device. An example of the thermal conductivity measuring device is the "TCi-3-A (product name)" manufactured by C-Therm Technologies.

[0038] The soft thermal conductive member 10 may contain a colorant, a base oil diffusion inhibitor, a thickener, etc. Note that, as the soft thermal conductive member 10, for example, a known paste-like soft conductive member such as the paste-like soft conductive member disclosed in WO 2022 / 186046 can be used.

[0039] The soft thermal conductive member 10 may be filled into the gap 32 by injection, or may be applied to the groove 31a to fill the gap 32. The soft thermal conductive member 10 may also be applied to the protrusion 21 to fill the gap 32. The soft thermal conductive member 10 may also be filled into the gap 32 by other methods.

[0040] The heat conduction structure 1 according to this embodiment has the above-described configuration, and the soft thermally conductive member 10 filling the gap 32 contacts the entire or nearly entire surface of the protrusion 21 of the heat-receiving member 2 in the groove 31a, and also contacts the entire or nearly entire surface of the groove 31a of the receiving member 3. Furthermore, the soft thermally conductive member 10 is soft and does not flow, at least within the temperature range in which the heat conduction structure 1 is used, and does not or hardly deform without the action of an external force, but plastically deforms when subjected to an external force of a predetermined magnitude. Thus, in the heat conduction structure 1, the soft thermally conductive member 10 provides strong adhesion between the protrusion 21 of the heat-receiving member 2 and the groove 31a of the receiving member 3. Therefore, the heat conduction structure 1 can improve the efficiency of heat conduction between the heat-receiving member 2 and the receiving member 3.

[0041] Furthermore, the soft thermally conductive member 10 fills the gap 32 and maintains its shape. Therefore, regardless of the shape of the protruding portion 21 of the heat-dissipating member 2 and the shape of the accommodation portion 31 of the receiving member 3, the soft thermally conductive member 10 contacts the entire surface or almost the entire surface of the protruding portion 21 in the groove 31a, and also contacts the entire surface or almost the entire surface of the groove 31a. Therefore, unlike when the protruding portion 21 of the heat-dissipating member 2 and the accommodation portion 31 of the receiving member 3 are in direct contact to form a thermal conduction path, high dimensional accuracy is not required for the protruding portion 21 of the heat-dissipating member 2, and high dimensional accuracy is not required for the accommodation portion 31 of the receiving member 3.

[0042] Furthermore, even if the protruding portion 21 of the heat-dissipating member 2 or the accommodation portion 31 of the receiving member 3 is deformed, or even if the relative position between the protruding portion 21 of the heat-dissipating member 2 and the accommodation portion 31 of the receiving member 3 is changed, the soft thermally conductive member 10 follows this deformation or change in relative position, and maintains contact with the entire surface or almost the entire surface of the protruding portion 21 in the groove 31 a, and with the entire surface or almost the entire surface of the groove 31 a. Therefore, the heat conducting structure 1 can maintain high thermal conduction efficiency between the heat-dissipating member 2 and the receiving member 3 even if the protruding portion 21 of the heat-dissipating member 2 or the accommodation portion 31 of the receiving member 3 is deformed, or even if the relative position between the protruding portion 21 of the heat-dissipating member 2 and the accommodation portion 31 of the receiving member 3 is changed.

[0043] As described above, the heat conduction structure 1 according to the first embodiment of the present invention can achieve good heat dissipation.

[0044] Next, a second embodiment of the present invention will be described. Fig. 2 is a cross-sectional view showing a schematic configuration of a heat conduction structure 4 according to the second embodiment of the present invention. The heat conduction structure 4 according to this embodiment differs from the heat conduction structure 1 described above in the form of the thermal connection portion. Hereinafter, regarding the configuration of the heat conduction structure 4, components that are the same as or have similar functions to those of the heat conduction structure 1 described above will be assigned the same reference numerals and their description will be omitted, and different components will be described.

[0045] 2, in the heat conduction structure 4, the soft thermally conductive member 10 is also filled between the heat-receiving member 2 and the receiving member 3. The heat-receiving member 2 and the receiving member 3 have thermal connection parts 25 and 35, respectively, which are parts for thermally connecting them to each other, as shown in Fig. 2, for example. The soft thermally conductive member 10 is filled between the thermal connection part 25 of the heat-receiving member 2 and the thermal connection part 35 of the receiving member 3.

[0046] The thermal connection portion 25 of the heat-receiving member 2 is a surface 26, as shown in Fig. 2. The thermal connection portion 35 of the receiving member 3 is a surface 36 that faces the surface 26, which is the thermal connection portion 25 of the heat-receiving member 2, as shown in Fig. 2. The soft thermally conductive member 10 is filled between the surface 26, which is the thermal connection portion 25 of the heat-receiving member 2, and the surface 36, which is the thermal connection portion 35 of the receiving member 3. Note that the surfaces 26 and 36 are not limited to smooth surfaces, and may be surfaces of any shape, such as surfaces with irregularities. Furthermore, the surfaces 26 and 36 are not limited to being continuous surfaces, and may be surfaces having multiple separated surfaces.

[0047] In the heat conduction structure 4, the soft heat conduction member 10 is in contact with the entire or almost entire surface of the surface 26 of the heat-receiving member 2, and is also in contact with the entire or almost entire surface of the surface 36 of the receiving member 3. This increases the adhesion between the surface 26 of the heat-receiving member 2 and the surface 36 of the receiving member 3 via the soft heat conduction member 10. Therefore, the heat conduction structure 4 also functions in the same way as the above-mentioned heat conduction structure 1, and can increase the efficiency of heat conduction between the heat-receiving member 2 and the receiving member 3.

[0048] As described above, the heat conduction structure 4 according to the second embodiment of the present invention can achieve good heat dissipation.

[0049] Next, a modified example of the heat conduction structure 4 according to the second embodiment of the present invention will be described. Fig. 3 is a cross-sectional view showing a schematic configuration of the modified example of the heat conduction structure 4. As shown in Fig. 3, in the modified heat conduction structure 4, a part of the surface 26 that is the thermal connection portion 25 of the heat-receiving member 2 and a part of the surface 36 that is the thermal connection portion 35 of the receiving member 3 are in direct contact with each other, and a gap 37 is formed between the part of the surface 26 of the thermal connection portion 25 of the heat-receiving member 2 and the part of the surface 36 of the thermal connection portion 35 of the receiving member 3. A soft thermally conductive member 10 is filled in this gap 37.

[0050] In the heat conduction structure 4 according to the modified example, the soft thermally conductive member 10 also contacts the entire or almost the entire part of the surface 26 of the heat-receiving member 2 that forms the gap 37, and also contacts the entire or almost the entire part of the surface 36 of the receiving member 3 that forms the gap 37. This increases the adhesion between the surface 26 of the heat-receiving member 2 and the surface 36 of the receiving member 3 through direct contact and contact via the soft thermally conductive member 10. Therefore, the heat conduction structure 4 according to the modified example can also increase the efficiency of heat conduction between the heat-receiving member 2 and the receiving member 3.

[0051] For example, if the dimensional accuracy of the surface 36 of the receiving member 3 is low or if the surface 36 of the receiving member 3 is deformed, a gap 37 is formed between a portion of the surface 26 of the heat-dissipating member 2 and a portion of the surface 36 of the receiving member 3, as in the heat conduction structure 4 according to the modified example. Furthermore, if the dimensional accuracy of the surface 26 of the heat-dissipating member 2 is low or if the surface 26 of the heat-dissipating member 2 is deformed, a gap 37 is formed between a portion of the surface 26 of the heat-dissipating member 2 and a portion of the surface 36 of the receiving member 3, as in the heat conduction structure 4 according to the modified example. Even in such cases, the soft thermally conductive member 10 filling the gap 37 improves the adhesion between the surface 26 of the heat-dissipating member 2 and the surface 36 of the receiving member 3. This improves the efficiency of heat conduction between the heat-dissipating member 2 and the receiving member 3. Furthermore, the heat conduction structure 4 does not require high dimensional accuracy for the surface 26 of the heat-dissipating member 2, and does not require high dimensional accuracy for the surface 36 of the receiving member 3.

[0052] Next, an example of the heat conduction structure 1 according to the first embodiment of the present invention will be described. FIG. 4 is a cross-sectional view showing a schematic configuration of an example of the heat conduction structure 1 according to the first embodiment of the present invention. The heat conduction structure 1 according to the example is a heat conduction structure for dissipating heat from laminated cells in a secondary battery configured by stacking laminated cells in a housing. Note that a laminated cell is a battery cell that uses a laminate film, in which insulating resin films are bonded to both sides of a metal foil such as aluminum foil or stainless steel foil, as an exterior body for housing the battery elements. Note that FIG. 4 shows a portion of a secondary battery.

[0053] In the heat conduction structure 1 according to this embodiment, the heat-dissipating member 2 is a laminated cell of a secondary battery 5, and the receiving member 3 is a housing for the secondary battery 5. The thermal connection portion 20 of the heat-dissipating member (laminated cell) 2 is a positive electrode current collector tab 21a and a negative electrode current collector tab 21b that protrude from an exterior body 40 of the laminated cell 2, which is composed of laminate films 41 and 42. The positive electrode current collector tab 21a and the negative electrode current collector tab 21b form the protruding portion 21 of the heat conduction structure 1. As shown in FIG. 4 , the laminate films 41 and 42 are films formed by laminating a metal sheet 44 such as aluminum foil, an inner thermoplastic resin layer 43, and an outer insulating resin layer 45. An electrode laminate portion 46 is housed within the exterior body 40. The electrode laminate portion 46 has a configuration in which, for example, positive and negative electrode plates are alternately stacked with separators interposed therebetween.

[0054] The thermal connection portion 30 of the receiving member (housing) 3 is a housing portion 31 formed in the housing 3. The housing portion 31 is formed so as to be able to house the positive electrode current collector tab 21a and the negative electrode current collector tab 21b of the laminated cell 2 with a gap 32 therebetween, and specifically is, for example, a recess forming a groove 31a. A housing portion 31 is provided for each laminated cell 2. A housing portion 31 may be provided for each of the positive electrode current collector tab 21a and the negative electrode current collector tab 21b, or one housing portion 31 may be provided for each of the positive electrode current collector tab 21a and the negative electrode current collector tab 21b.

[0055] The housing 3 is made of, for example, a thermally conductive resin, and the thermal conductivity of the housing 3 is lower than the thermal conductivity of the positive electrode current collector tab 21 a and the negative electrode current collector tab 21 b of the laminated cell 2 .

[0056] As shown in FIG. 4 , the positive electrode current collector tab 21a and the negative electrode current collector tab 21b of the laminated cell 2 are inserted into a groove 31a in the housing 3. A gap 32 extends between the entire surface of the positive electrode current collector tab 21a in the groove 31a and the entire surface of the groove 31a facing the positive electrode current collector tab 21a. The gap 32 also extends between the entire surface of the negative electrode current collector tab 21b in the groove 31a and the entire surface of the groove 31a facing the negative electrode current collector tab 21b. A soft thermal conductive member 10 is filled in the gap 32. As shown in FIG. 4 , the soft thermal conductive member 10 is in contact with the entire surface of the positive electrode current collector tab 21a in the groove 31a, the entire surface of the negative electrode current collector tab 21b in the groove 31a, and the entire surface of the groove 31a. Note that the soft thermal conductive member 10 does not have to fill the entire gap 32.

[0057] As described above, in the secondary battery 5, the soft thermally conductive member 10 filling the gap 32 is in contact with the entire surface or substantially the entire surface of the positive electrode current collector tab 21a and the negative electrode current collector tab 21b in the groove 31a of the casing 3, and is also in contact with the entire surface or substantially the entire surface of the groove 31a of the casing 3. As a result, similar to the above-described heat conduction structure 1, in the secondary battery 5, the soft thermally conductive member 10 improves adhesion between the positive electrode current collector tab 21a and the negative electrode current collector tab 21b of the laminated cell 2 and the groove 31a of the casing 3. Therefore, in the secondary battery 5, the heat conduction structure 1 can increase the thermal conductivity between the laminated cell 2 and the casing 3, and can improve the heat dissipation effect from the laminated cell 2 to the casing 3. Furthermore, the heat conduction structure 1 can add heat dissipation from the positive electrode current collector tab 21a and the negative electrode current collector tab 21b to the laminated cell 2, thereby further enhancing the heat dissipation effect for the laminated cell 2. As a result, even if the output of the secondary battery 5 increases and the temperature of the electrode stacking portion 46 of the laminated cell 2 rises, the heat inside the laminated cell 2 can be effectively dissipated to the housing 3 via the soft thermally conductive member 10. This makes it possible to prevent damage to the laminated cell 2 due to heat, and allows the secondary battery 5 to be used at a higher output.

[0058] As described above, the thermal conductivity of the thermally conductive resin that makes up the housing 3 is lower than the thermal conductivity of the positive electrode current collector tab 21 a and the negative electrode current collector tab 21 b of the laminated cell 2. Therefore, heat within the laminated cell 2 can be efficiently dissipated by the housing 3 via the soft thermally conductive member 10.

[0059] The thermal conduction structure 1 in the laminated cell 2 of the secondary battery 5 described above is one example of the thermal conduction structure 1 according to the first embodiment of the present invention, and the specific application of the thermal conduction structure 1 according to the first embodiment of the present invention is not limited to the laminated cell 2 of the secondary battery 5 described above, but can also be applied to other parts and devices such as bus bars and connectors of electronic components and electronic devices.

[0060] Next, an example of the heat conduction structure 4 according to the second embodiment of the present invention will be described. Fig. 5 is a cross-sectional view showing a schematic configuration of the example of the heat conduction structure 4 according to the second embodiment of the present invention. The heat conduction structure 4 according to the example is a heat conduction structure for dissipating heat from a coil of a brushless motor in an in-wheel motor.

[0061] In the heat conduction structure 4 according to this embodiment, the heat dissipation member 2 is a stator coil of a brushless motor 6, and the receiving member 3 is a stator holder of the brushless motor 6. A thermal connection portion 25 of the heat dissipation member (stator coil) 2 is a surface (coil bundle surface) 26 of the stator coil 2 bundle formed by the bundle of stator coils 2 wound around each core 7 of the stator. Furthermore, a thermal connection portion 35 of the receiving member (stator holder) 3 is a surface 36 formed on the stator holder 3. The surface 36 of the stator holder 3 faces the coil bundle surface 26. The soft thermally conductive member 10 is filled between the coil bundle surface 26 of the stator coil 2 and the surface 36 of the stator holder 3.

[0062] In the heat conduction structure 4, the soft heat conduction member 10 is in contact with the entire or almost entire coil bundle surface 26 of the stator coil 2, and is also in contact with the entire or almost entire surface of the face 36 of the stator holder 3. As a result, the coil bundle surface 26 of the stator coil 2 and the face 36 of the stator holder 3 are thermally connected via the soft heat conduction member 10. Also, the adhesion between the coil bundle surface 26 of the stator coil 2 and the face 36 of the stator holder 3 is high via the soft heat conduction member 10. Note that the soft heat conduction member 10 may be filled in the space between the stator coils 2 wound around adjacent cores 7 of the stator.

[0063] The stator holder 3 is made of, for example, a thermally conductive resin, and the thermal conductivity of the stator holder 3 is lower than the thermal conductivity of the stator coil 2 of the brushless motor 6 .

[0064] As described above, in the brushless motor 6 of the in-wheel motor, the soft heat-conducting member 10 is in contact with the entire or nearly entire coil bundle surface 26 of the stator coil 2, and is also in contact with the entire or nearly entire surface of the face 36 of the stator holder 3. In this way, the soft heat-conducting member 10 improves the adhesion between the coil bundle surface 26 of the stator coil 2 and the face 36 of the stator holder 3. Therefore, in the brushless motor 6 of the in-wheel motor, the heat-conducting structure 4 can increase the efficiency of heat conduction between the stator coil 2 and the stator holder 3, and can improve the heat dissipation effect from the stator coil 2 to the stator holder 3. Furthermore, the heat-conducting structure 4 can add heat dissipation from the coil bundle surface 26 of the stator coil 2 to the brushless motor 6, thereby further increasing the heat dissipation effect of the brushless motor 6.

[0065] As described above, the thermal conductivity of the thermally conductive resin that makes up the stator holder 3 is lower than the thermal conductivity of the stator coil 2 of the brushless motor 6. Therefore, the heat from the stator coil 2 can be efficiently dissipated by the stator holder 3 via the soft thermally conductive member 10.

[0066] The heat conduction structure 4 in the brushless motor 6 of the in-wheel motor described above may be filled between the coil bundle surface 26 facing the core 7 or insulator (not shown) of the stator coil 2 and the core 7 or the insulator (not shown). The heat conduction structure 4 in the brushless motor 6 of the in-wheel motor described above is one example of the heat conduction structure 4 according to the second embodiment of the present invention, and the specific application of the heat conduction structure 4 according to the second embodiment of the present invention is not limited to the brushless motor 6 of the in-wheel motor described above, but can also be applied to other parts and devices such as bus bars and connectors of electronic components and electronic devices, slot liners and rotors of motors, etc.

[0067] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0068] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. Furthermore, the above-described embodiments do not limit the scope of the present invention, and the present invention may include any and all applications. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those illustrated and may be modified as appropriate. For example, the present invention includes differences that arise during implementation due to manufacturing tolerances, etc. Furthermore, components illustrated in different embodiments may be partially substituted or combined within the scope of technical inconsistency. Furthermore, the various configurations may be selectively combined as appropriate to achieve at least some of the above-described problems and effects.

[0069] 1, 4 Heat conduction structure, 2 Heat dissipation member, laminated cell, stator coil, 3 Receiving member, housing, stator holder, 5 Secondary battery, 6 Brushless motor, 7 Core, 10 Soft heat conduction member, 20, 25 Thermal connection portion, 21 Protrusion, 21a Positive electrode current collecting tab, 21b Negative electrode current collecting tab, 26 Surface, coil bundle surface, 30, 35 Thermal connection portion, 31 Housing portion, 31a Groove, 32 Gap, 36 Surface, 37 Gap, 40 Outer body, 41, 42 Laminate film, 43 Thermoplastic resin layer, 44 Metal sheet, 45 Insulating resin layer, 46 Electrode laminate portion

Claims

1. A heat conduction structure for conducting heat from a heat-dissipating member to a receiving member, comprising a soft heat-conducting member which is a soft member having thermal conductivity, the soft heat-conducting member being a member capable of maintaining its shape, and the soft heat-conducting member being filled between the heat-dissipating member and the receiving member.

2. The heat conduction structure according to claim 1, wherein the thermal conductivity of the soft heat conduction member is lower than the thermal conductivity of the heat-dissipating member.

3. The heat conducting structure according to claim 1, wherein the soft heat conducting member is a paste-like composite material having heat conductivity.

4. The heat conducting structure according to claim 3, wherein the soft heat conducting member includes grease and heat conducting particles.

5. The heat conduction structure according to claim 1, wherein the receiving member is made of a thermally conductive resin, and the thermal conductivity of the receiving member is lower than the thermal conductivity of the heat-dissipating member.

6. The heat conduction structure according to claim 1, wherein the heat dissipation member and the receiving member each have a thermal connection portion which is a portion for thermally connecting them to each other, and the soft thermally conductive member is filled between the thermal connection portion of the heat dissipation member and the thermal connection portion of the receiving member.

7. The heat conduction structure according to claim 6, wherein the thermal connection portion of the heat dissipation member is a protruding portion that protrudes, the thermal connection portion of the receiving member is a housing portion that is capable of housing the protruding portion with a gap, and the gap is filled with the soft thermal conductive member.

8. The heat transfer structure according to claim 7, wherein the container is a recess forming a groove.

9. The heat conduction structure according to claim 6, wherein the thermal connection portion of the heat-dissipating member is a surface, the thermal connection portion of the receiving member is a surface facing the surface of the thermal connection portion of the heat-dissipating member, and the soft thermal conductive material is filled between the surface of the thermal connection portion of the heat-dissipating member and the surface of the thermal connection portion of the receiving member.

Images