Heat transfer member, method for producing same, and battery

Abstract

[Problem] To increase the thermal conduction of a heat transfer member that is interposed between a heat source and a cooling member.　[Solution] The present invention relates to a heat transfer member 1 which is capable of transferring heat from a heat source to a cooling member by being interposed between the heat source and the cooling member, and which is provided with: an elastic sheet body 10 comprising an elastic sheet 11 that is elastically deformable at least in the thickness direction, and a highly lubricated layer 16 that is formed on at least one surface of the elastic sheet 11 in the thickness direction and has a higher lubricity than the elastic sheet 11; and a heat transfer film 20 which is provided so as to meander in a specific direction that is perpendicular to the thickness direction of the elastic sheet body 10 within the sheet surface, while being alternatively exposed in the front-side surface and the back-side surface of the elastic sheet body 10 in the thickness direction. The present invention also relates to: a method for producing a heat transfer member; and a battery.

Description

Heat conducting member, manufacturing method thereof, and battery Cross Reference

[0001] The contents of the patents, patent applications and publications cited throughout this application are hereby incorporated by reference.

[0002] The present invention relates to a heat conducting member, a manufacturing method thereof, and a battery including the heat conducting member.

[0003] Control systems for automobiles, aircraft, ships, and home and commercial electronic devices are becoming more precise and complex, and as a result, the integration density of small electronic components on circuit boards is steadily increasing. As a result, there is a strong demand for solutions to the problems of electronic component failure and shortened lifespan caused by heat generation around the circuit board.

[0004] Conventionally, rapid heat dissipation from circuit boards has been achieved by constructing the circuit board itself from a material with excellent heat dissipation properties, attaching a heat sink, or driving a cooling fan, either singly or in combination. Among these methods, constructing the circuit board itself from a material with excellent heat dissipation properties, such as diamond, aluminum nitride (AlN), or cubic boron nitride (cBN), significantly increases the cost of the circuit board. Furthermore, the placement of a cooling fan presents problems such as the risk of failure of the rotating device, the need for maintenance to prevent failure, and the difficulty of securing installation space. In contrast, heat dissipation fins are simple components that can increase surface area and enhance heat dissipation by forming numerous columnar or flat protrusions made of a highly thermally conductive metal (e.g., aluminum). Therefore, they are widely used as heat dissipation components.

[0005] Currently, there is a growing global movement to gradually replace conventional gasoline- and diesel-powered vehicles with electric vehicles (EVs) in order to reduce the burden on the global environment. Electric vehicles are becoming increasingly popular, particularly in European countries such as France, the Netherlands, and Germany, as well as China. The widespread adoption of EVs requires the development of high-performance batteries and the installation of numerous charging stations. Technological development to improve the charging and discharging capabilities of lithium-based automotive batteries is particularly important. It is well known that automotive batteries cannot fully perform their charging and discharging functions at temperatures above 60°C. Furthermore, testing is currently underway to achieve high-speed, contactless battery charging. To prevent battery life loss, it is also necessary to address the heat generated by overcharging. For these reasons, improving the heat dissipation capabilities of batteries, similar to the circuit boards described above, is becoming increasingly important.

[0006] As a heat conduction member for promoting heat dissipation from the above-mentioned heat source, for example, a member having thin sheets with excellent thermal conductivity exposed alternately on the front and back of a resin sheet is known (see Patent Documents 1 and 2).

[0007] JP 2015-201534 A JP 2012-031242 A

[0008] However, the above-mentioned conventionally known thermal conductive members have the following problems. When a thermal conductive member is interposed between a heat source and a cooling member, close contact between the thermal conductive member and the heat source or the cooling member is important to improve the thermal conductivity from the heat source to the cooling member. For this reason, it is preferable to compress the thermal conductive member by applying pressure in the thickness direction of the thermal conductive member. However, when the thermal conductive member is sandwiched between the heat source and the cooling member, the thermal conductive film exposed on the front or back surface of the thermal conductive member may be damaged. Furthermore, the thermal conductive film may be damaged during the manufacturing process of the thermal conductive member. This may result in reduced thermal conduction from the heat source to the cooling member via the thermal conductive member. Addressing these problems will also contribute to the achievement of the applicant's sustainable development goal of "ensuring access to affordable, reliable, sustainable, and modern energy for all."

[0009] The present invention has been made in view of the above-mentioned problems, and has an object to improve the thermal conductivity of a heat conduction member interposed between a heat source and a cooling member.

[0010] (1) To achieve the above object, one embodiment of a heat conduction member is interposed between a heat source and a cooling member to transfer heat from the heat source to the cooling member, and includes an elastic sheet having an elastically deformable elastic sheet at least in the thickness direction, a high-lubricity layer formed on at least one surface of the elastic sheet in the thickness direction and having a higher lubricity than the elastic sheet, and a heat conduction film that is exposed alternately on the front and back surfaces of the elastic sheet in the thickness direction and that meanders in a predetermined direction within the sheet plane perpendicular to the thickness direction of the elastic sheet. (2) In another embodiment of a heat conduction member, preferably, the high-lubricity layer may be formed on both surfaces of the elastic sheet in the thickness direction. (3) In another embodiment of a heat conduction member, preferably, the high-lubricity layer may be a resin film. (4) In another embodiment of the heat conduction member, the elastic sheet preferably has a tapered or curved portion at an edge that contacts the heat conduction film, and the high-lubricity layer may cover the tapered or curved portion. (5) In another embodiment of the heat conduction member, the elastic sheet preferably is a foam sheet. (6) In one embodiment of the heat conduction member, a method for manufacturing any of the heat conduction members described above includes a high-lubricity layer forming step of forming the high-lubricity layer on at least one surface in the thickness direction of the elastic sheet, a through-hole forming step of forming a plurality of through-holes at predetermined intervals in the elastic sheet, penetrating from the front surface to the back surface in the thickness direction, a heat conduction film arranging step of arranging the heat conduction film on the front surface of the elastic sheet so as to cover the through-holes, and an elastic sheet piece inserting step of inserting elastic sheet pieces into the through-holes from above the heat conduction film to expose the heat conduction film from the back surface. (7) In another embodiment of the method for manufacturing a heat conduction member, the high-lubricity layer forming step may preferably be a step of forming the high-lubricity layer on both sides of the elastic sheet in the thickness direction.(8) In another embodiment of the method for manufacturing a heat conduction member, the high-slip layer forming step may preferably be a step of laminating a resin film on at least one surface of the elastic sheet in the thickness direction. (9) In another embodiment of the method for manufacturing a heat conduction member, the high-slip layer forming step may preferably be a step of forming a tapered or curved portion on the edge of the elastic sheet that contacts the heat conduction film prior to the high-slip layer forming step. (10) In another embodiment of the method for manufacturing a heat conduction member, the through-hole forming step may preferably be a step of forming the through-hole and rotating the elastic sheet piece that connects to a part of the opening of the through-hole to retract it from the through-hole, and the elastic sheet piece inserting step may be a step of rotating the elastic sheet piece toward the through-hole and inserting it into the through-hole. (11) In one embodiment of the battery, the heat source is one or more battery cells, the cooling member is a housing that houses the battery cells, and any of the heat conduction members described above is interposed between the battery cells and the housing.

[0011] According to the present invention, it is possible to enhance the thermal conductivity of the heat conducting member interposed between the heat source and the cooling member.

[0012] FIG. 1 shows a plan view, a right side view, and a front view of a heat conduction member according to an embodiment of the present invention. FIG. 2 shows a perspective view of the heat conduction member of FIG. 1. FIG. 3 shows a cross-sectional view of the heat conduction member of FIG. 1 taken along line A-A in the plan view, and an enlarged view of part B. FIG. 4 shows an enlarged cross-sectional view, viewed in the same manner as FIG. 3, of a portion of the manufacturing process of the heat conduction member of FIG. 1. FIG. 5 shows a flowchart including main steps of a manufacturing method of a heat conduction member according to an embodiment of the present invention. FIG. 6 shows a perspective view illustrating an example of a manufacturing method of a heat conduction member according to an embodiment of the present invention. FIG. 7 shows a cross-sectional view, viewed in the same manner as FIG. 3, of an example of a manufacturing method of a heat conduction member according to an embodiment of the present invention. FIG. 8 shows a perspective view illustrating an example of a manufacturing method of a heat conduction member according to an embodiment of the present invention. FIG. 9 shows a perspective view illustrating a modification of the manufacturing method of FIG. 8. FIG. 10 shows an enlarged view, viewed in the same manner as part B of FIG. 3, of a modification of the heat conduction member. FIG. 11 shows a longitudinal cross-sectional view of a battery including a heat conduction member. FIG. 12 shows a cross-sectional view of a battery cell placed horizontally on a heat-conducting member with its side surface in contact with the heat-conducting member, a partially enlarged view thereof, and a partially cross-sectional view of the battery cell when it expands during charging and discharging.

[0013] 1...heat conduction member, 10, 10a...elastic sheet body, 10b...elastic sheet body piece, 11, 11a...elastic sheet (one example is a foam sheet), 11b...elastic sheet piece (one example is a foam sheet), 12...elongated through hole (one example of a through hole), 13...short side (one example of a part of an opening), 15...tapered portion (or curved portion), 16...high-slip layer (one example is a resin film), 17...notch, 20...heat conduction film, 30, 31...battery cell (one example of a heat source), 40...battery (one example of a heat source), 41...casing, 42...bottom (one example of a cooling member).

[0014] Next, various embodiments of the present invention will be described with reference to the drawings. Note that the various embodiments described below do not limit the scope of the invention as claimed, and not all of the elements and combinations thereof described in the various embodiments are necessarily essential to the solution of the present invention.

[0015] <Heat Conduction Member and Manufacturing Method Thereof> (First Embodiment) Fig. 1 shows a plan view, a right side view, and a front view of a heat conduction member according to an embodiment of the present invention. Fig. 2 shows a perspective view of the heat conduction member of Fig. 1. Hereinafter, the thickness direction, width direction, and length direction refer to the direction of the shortest side, the direction of the second longest side after the thickness direction, and the direction of the longest side of a rectangular parallelepiped, respectively.

[0016] The thermally conductive member 1 according to this embodiment is a member interposed between a heat source and a cooling member to transfer heat from the heat source to the cooling member. The thermally conductive member 1 includes an elastic sheet 10 and a thermally conductive film 20. The elastic sheet 10 includes an elastic sheet 11 and a high-lubrication layer 16. The elastic sheet 11 is elastically deformable at least in the thickness direction. As long as the elastic sheet 11 is elastically deformable in the thickness direction, it may also be elastically deformable in the width and length directions. The high-lubrication layer 16 is a layer formed on at least one surface of the elastic sheet 11 in the thickness direction and has higher slipperiness than the elastic sheet 11. The thermally conductive film 20 is a film that is alternately exposed on the front and back surfaces of the elastic sheet 10 in the thickness direction and extends in a serpentine pattern in a predetermined direction (here, the length direction of the elastic sheet 10) within the sheet plane at a right angle to the thickness direction of the elastic sheet 10. The elastic sheet 10 preferably holds the thermally conductive film 20 by penetrating the thermally conductive film 20 in the thickness direction and arranging the recesses and protrusions in a repeated pattern. That is, the elastic sheet 10 holds the thermally conductive film 20 so that the thermally conductive film 20 is exposed at predetermined intervals on the surface facing the heat source and the surface facing the cooling member.

[0017] In this embodiment, the elastic sheet 11 is preferably a thin sheet whose thickness is significantly smaller than its width and length. In this embodiment, the high-lubrication layer 16 is preferably a film whose width and length are equivalent to those of the elastic sheet 11 but whose thickness is thinner than that of the elastic sheet 11. Furthermore, in this embodiment, the high-lubrication layer 16 is preferably formed on both sides of the elastic sheet 11 in the thickness direction. However, the high-lubrication layer 16 may be formed on only one side of the elastic sheet 11 in the thickness direction. The heat conductive film 20 according to this embodiment is a film with higher thermal conductivity and lower stretchability than the elastic sheet 11. The heat conductive film 20 is exposed on the front surface of the elastic sheet 10 in the length direction, preferably at a constant pitch. Similarly, the heat conductive film 20 is exposed on the back surface of the elastic sheet 10 in the length direction, preferably at a constant pitch. However, the pitch may not be constant and may vary.

[0018] An important function of the elastic sheet 11 is to provide the thermal conductive member 1 with ease of deformation and recovery force. The recovery force is due to the elastic deformability of the elastic sheet 11. The ease of deformation is due to the flexibility of the elastic sheet 11. There are no restrictions on the thickness of the elastic sheet 11, but it is preferably 0.2 to 20 mm, and more preferably 0.5 to 10 mm. Furthermore, it is preferable that the thickness of the elastic sheet 11 be greater than the thickness of the thermal conductive film 20.

[0019] The elastic sheet 11 is preferably configured to include a thermosetting elastomer such as silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber (NBR), or styrene butadiene rubber (SBR); a thermoplastic elastomer such as a urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, or fluorine-based elastomer, or a composite thereof. The elastic sheet 11 is preferably configured to include a material with high heat resistance so that it can maintain its shape without melting or decomposing due to the heat transmitted through the thermally conductive film 20. In this embodiment, the elastic sheet 11 is more preferably configured from a urethane-based elastomer impregnated with silicone or silicone rubber. In this embodiment, the elastic sheet 11 is a silicone rubber sheet. The elastic sheet 11 may include Al in the rubber to enhance its thermal conductivity. ２ O ３ The elastic sheet 11 may be formed by dispersing fillers such as AlN, cBN, hBN, diamond particles, etc. More preferably, the elastic sheet 11 is a highly cushioning sponge containing air bubbles therein. In this embodiment, the elastic sheet 11 is a foam sheet. Furthermore, the term "elastic sheet" refers to a member that is highly flexible and elastically deformable, and in this sense, it can also be read as a "cushion member," "cushion sheet," or "rubber-like elastic body."

[0020] The high-slip layer 16 is a layer that has a lower coefficient of friction than the area inside the layer and is therefore slippery. An important function of the high-slip layer 16 is to increase the slipperiness of at least one surface of the elastic sheet 11 in the thickness direction. By increasing the slipperiness of at least one surface of the elastic sheet 11 in the thickness direction in this way, when the thermally conductive film 20 is inserted through the elastic sheet 10 in the thickness direction to form repeated irregularities, friction between the thermally conductive film 20 and the elastic sheet 10 is reduced, and damage to the thermally conductive film 20 can be prevented.

[0021] The high-lubricity layer 16 is preferably a resin film. In particular, when the elastic sheet 11 is a foamed sponge sheet, using a resin film for the high-lubricity layer 16 can reduce friction between the heat conductive film 20 and the surface of the elastic sheet 11 (i.e., the high-lubricity layer 16). There are no particular restrictions on the resin film, but polyimide (Pi), polyethylene terephthalate (PET), polycarbonate (PC), etc. can be used. The high-lubricity layer 16 is preferably made of a material with high heat resistance that can maintain its shape without melting or decomposing due to heat transmitted through the heat conductive film 20. In this embodiment, the high-lubricity layer 16 is more preferably a PET film. The thickness of the high-lubricity layer 16 is not restricted as long as it does not impair the cushioning properties of the elastic body, but it is preferably 3 to 10 μm, more preferably 3 to 5 μm.

[0022] The material of the thermally conductive film 20 is not particularly limited, but is preferably a flexible member containing at least one of metal, carbon, and ceramic. The thermally conductive film 20 is more preferably a carbon film or a carbon-containing resin film. The thermally conductive film 20 is preferably a film composed of 90% or more by mass of carbon. For example, the thermally conductive film 20 can be a graphite film formed by baking a resin. However, the thermally conductive film 20 may also be a film containing carbon and resin. In such a case, the resin may be a synthetic fiber, preferably aramid fiber. In this application, "carbon" is broadly interpreted to include any structure consisting of carbon (element symbol: C), such as graphene, graphite, carbon black with lower crystallinity than graphite, carbon nanotubes, diamond, and diamond-like carbon with a structure similar to diamond. In this embodiment, the thermally conductive film 20 can be a thin film formed by hardening a material in which graphite fibers or carbon particles are dispersed in a resin. The thermally conductive film 20 may be a mesh of carbon fiber, or may be a blended or blended knitted material. Note that various fillers, such as graphite fiber, carbon particles, and carbon fiber, are all included in the concept of carbon filler. The thermally conductive film 20 may also be referred to as a "thermally conductive sheet."

[0023] When the thermally conductive film 20 is a film containing carbon and resin, the resin may account for more than 50% by mass or less of the total mass of the thermally conductive film 20. In other words, the thermally conductive film 20 may be made primarily of resin, as long as it does not significantly impede thermal conduction. For example, a thermoplastic resin can be used as the resin. A thermoplastic resin with a high melting point that does not melt when conducting heat from a heat source is preferred. Suitable examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyamide-imide (PAI), and aromatic polyamide (aramid fiber). Before the thermally conductive film 20 is molded, the resin is dispersed in the gaps between the carbon fillers, for example, in the form of particles or fibers. In addition to the carbon filler and resin, the thermally conductive film 20 may contain Al as a filler to further enhance thermal conduction. ２ O ３ , AlN, or diamond may be dispersed therein. Also, rubber, which is softer than resin, may be used instead of resin. The thermally conductive film 20 may also be a film containing metal and / or ceramics instead of or in addition to the carbon described above. As the metal, a material with relatively high thermal conductivity such as aluminum, copper, or an alloy containing at least one of them may be selected. As the ceramic, Al ２ O ３ In addition, when the filler has anisotropic thermal conductivity, a method of controlling the orientation direction of the filler by a method such as flow orientation, stretch orientation, or magnetic field orientation during molding of the thermally conductive film may be used to further enhance thermal conductivity in a specific direction.

[0024] The thermally conductive film 20 may or may not have excellent electrical conductivity. The thermal conductivity of the thermally conductive film 20 is preferably 10 W / mK or higher. In this embodiment, the thermally conductive film 20 is preferably a graphite film, a material with excellent thermal and electrical conductivity. The thermally conductive film 20 is preferably a film with excellent flexibility (or bendability). There are no restrictions on its thickness, but a thickness of 0.02 to 3 mm is preferred, and 0.03 to 0.5 mm is more preferred. In this embodiment, the areas covered by the thermally conductive film 20 on the front and back surfaces of the elastic sheet 10 protrude from the front and back surfaces of the elastic sheet 10 by at least the thickness of the thermally conductive film 20. Note that the areas of the thermally conductive film 20 on either the front or back surface of the elastic sheet 10 may protrude from the corresponding surface of the elastic sheet 10 by at least the thickness of the thermally conductive film 20.

[0025] Fig. 3 shows a cross-sectional view of the heat conduction member of Fig. 1 taken along line A-A in the plan view thereof, and an enlarged view of a portion B. Fig. 4 shows an enlarged cross-sectional view, viewed from the same perspective as Fig. 3, of a part of the manufacturing process of the heat conduction member of Fig. 1.

[0026] The elastic sheet 11 preferably has a tapered portion 15 at the edge that contacts the heat conductive film 20. The elastic sheet 11 may have a curved portion instead of a tapered portion. Here, a tapered portion refers to a portion where a substantially right-angled edge corner is flattened to form an inclined surface. A curved portion refers to a portion where a substantially right-angled edge corner is arc-shaped, i.e., curved. The high-lubricity layer 16 preferably covers the tapered portion (or curved portion) 15 of the elastic sheet 11. Here, the high-lubricity layer 16 has a tapered portion 16a at the tapered portion 15. Even when the elastic sheet 11 has a curved portion, the high-lubricity layer 16 also has a curved portion at the curved portion. The heat conductive film 20 covers the tapered portion (or curved portion) 15 of the elastic sheet 11. Here, the heat conductive film 20 has a tapered portion 21 at the tapered portion 15. Even when the elastic sheet 11 has a curved portion, the thermally conductive film 20 also has a curved portion at the location of the curved portion. In this way, in the thermally conductive member 1, if the elastic sheet 11 has a tapered portion 15 or a curved portion at the edge that contacts the thermally conductive film 20 and the thermally conductive film 20 covers the tapered portion 15 or the curved portion of the elastic sheet 11, the risk of the thermally conductive film 20 being damaged at the edge of the elastic sheet 11 can be reduced even when the thermally conductive member 1 is sandwiched and compressed in the thickness direction between a heat source and a cooling member. Furthermore, in the thermally conductive member 1, if the high-lubricity layer 16 covers the tapered portion 15 or the curved portion of the elastic sheet 11, friction between the thermally conductive film 20 and the elastic sheet body 10 at the tapered portion 15 can be reduced, thereby reducing the risk of the thermally conductive film 20 being damaged. The high-lubricity layer 16 does not have to cover the tapered portion 15 or the curved portion of the elastic sheet 11.

[0027] Next, with reference to FIG. 4 showing an enlarged view of part B of the heat conductive member 1, a manufacturing method for exposing the heat conductive film 20 alternately on both sides of the elastic sheet 10 in the thickness direction will be described.

[0028] First, edge processing is performed on the edge of the elastic sheet 11 that contacts the heat conductive film 20 to form tapered portions 15. More specifically, long incisions 17 are formed in the width direction of the elastic sheet 11 at regular intervals along the length of the elastic sheet 11 (see FIG. 6(b)). Next, high-lubricity layers 16 are formed on both thicknesswise sides of the edge-processed elastic sheet 11 (see FIG. 6(c)). This forms an edge-processed elastic sheet body 10. Details of this edge processing and the formation of the high-lubricity layers 16 will be described later.

[0029] Then, elongated through holes 12 (an example of through holes) elongated in the width direction of the elastic sheet 10 are formed at regular intervals along the length of the elastic sheet 10. The elongated through holes 12 are preferably rectangular through holes surrounded by two adjacent notches formed by edge processing (see FIG. 6(d)). In this embodiment, the elastic sheet 10 has a total of 11 elongated through holes 12 along its length. By forming the elongated through holes 12 in this manner, an elastic sheet 11a is obtained in which tapered portions 15 are formed on the edges of the openings on the front side of the elongated through holes 12. Furthermore, the high-lubrication layer 16 has tapered portions 16a that cover the tapered portions 15 of the elastic sheet 11. Thus, an elastic sheet 10a is obtained in which elongated through holes 12 having tapered portions 15, 16a are formed. The tapered portions 15 may extend around the entire periphery of the openings, but in this embodiment, only the longitudinal edges of the elastic sheet 11 are tapered. A tapered portion 15 may also be formed on the edge of the opening on the back side of the elongated through hole 12. A curved portion may be provided instead of the tapered portion 15. Figure 4 illustrates the vicinity of one elongated through hole 12 and shows some of the manufacturing steps.

[0030] Next, a thermally conductive film 20 is placed on the front surface of the elastic sheet 10a. The thermally conductive film 20 preferably covers the elastic sheet 10a so as to cover all eleven elongated through holes 12. Next, the elastic sheet piece 10b is inserted into the elongated through holes 12, sandwiching the thermally conductive film 20 between them. The elastic sheet piece 10b is preferably a member cut out from the elastic sheet 10 when forming the elongated through holes 12. The elastic sheet piece 10b includes an elastic sheet 11b and a high-lubricity layer 16 covering both thickness-wise surfaces of the elastic sheet 11b. The elastic sheet 11b includes a tapered portion 15 on the edge of the surface facing the insertion direction (downward in FIG. 4 ). The high-lubricity layer 16 also includes a tapered portion 16a covering the tapered portion 15 of the elastic sheet 11b. This results in an elastic sheet piece 10b having tapered portions 15, 16a on the edge of the surface facing the insertion direction. As a result, when elastic sheet piece 10b is inserted into elongated through hole 12, elastic sheet piece 10b exposes heat conductive film 20 on the back side of elastic sheet 10a. Furthermore, on the front and back sides of elastic sheet 10a, heat conductive film 20 covers elastic sheet 11 and tapered portions 15, 16a of high-lubricity layer 16, and has tapered portions 21 at the locations of tapered portions 15, 16a. If adhesive layers are provided on elastic sheet 10a, elastic sheet piece 10b, and / or heat conductive film 20, heat conductive member 1 becomes a member in which elastic sheet 10 and heat conductive film 20 are fixed together.

[0031] Fig. 5 shows a flowchart including main steps of a method for manufacturing a heat conduction member according to an embodiment of the present invention. Fig. 6 shows a perspective view for explaining an example of a method for manufacturing a heat conduction member according to an embodiment of the present invention. Fig. 7 shows a cross-sectional view similar to Fig. 3 for explaining an example of a method for manufacturing a heat conduction member according to an embodiment of the present invention. Fig. 8 shows a perspective view for explaining an example of a method for manufacturing a heat conduction member according to an embodiment of the present invention. In Fig. 4, the manufacturing process is explained only for a portion of region B, but below, the manufacturing process is explained for the entire region of the heat conduction member.

[0032] The thermal conductive member 1 can be manufactured through an edge processing step (S100), a high-slip layer forming step (S110), a through-hole forming step (S120), a thermal conductive film arrangement step (S130), and an elastic sheet piece insertion step (S140). Steps S100 to S140 will be described in detail below with reference to FIGS. 5 to 8.

[0033] (1) Edge Processing Step (S100) This step forms tapered portions 15 (or curved portions) on the edge of the elastic sheet 11 that contacts the thermally conductive film 20. Specifically, elongated incisions 17 are formed in the width direction of the elastic sheet 11 at regular intervals along the length of the elastic sheet 11 (see FIG. 6(b)). In this embodiment, a total of 22 incisions 17 are formed on each thickness-wise surface of the elastic sheet 11. The shape of the incisions 17 is not particularly limited as long as it allows for the formation of tapered portions 15, but it is preferable that the incisions 17 have a generally V-shape in cross section (see FIG. 7(b)). In the edge processing step, preferably, multiple incisions 17 are formed on both thickness-wise surfaces of the elastic sheet 11. However, multiple incisions 17 may be formed only on one thickness-wise surface of the elastic sheet 11 in the edge processing step. The size and arrangement of the incisions 17 are not particularly limited, but are preferably designed appropriately depending on the intended use of the thermally conductive member 1. For example, in the edge processing step, when a curved portion is formed instead of the tapered portion 15, instead of the notch 17 having a generally V-shape in cross section, a notch having a curved hypotenuse portion of a generally V-shape in cross section can be formed.

[0034] (2) High-Smoothing Layer Forming Step (S110) This step is a step of forming a high-smoothing layer 16 on at least one surface of the elastic sheet 11 in the thickness direction. In this embodiment, the high-smoothing layer forming step forms the high-smoothing layer 16 on both surfaces of the elastic sheet 11 in the thickness direction. Specifically, the high-smoothing layer 16 is laminated on both surfaces of the edge-finished elastic sheet 11 in the thickness direction (see FIGS. 6(c) and 7(c)). This forms the elastic sheet body 10. In the high-smoothing layer forming step, the high-smoothing layer 16 is preferably laminated so as to cover all of the incisions 17 of the elastic sheet 11 (see FIG. 7(d)). In the high-smoothing layer forming step, an adhesive layer such as an adhesive may be interposed between the elastic sheet 11 and the high-smoothing layer 16, or the high-smoothing layer 16 may be laminated without an adhesive layer interposed therebetween. In the high-lubricity layer forming step, the high-lubricity layer 16 may be formed on only one surface of the elastic sheet 11 in the thickness direction.

[0035] (3) Through-hole forming step (S120) This step is a step of forming a plurality of elongated through-holes 12 at predetermined intervals in the elastic sheet 10, penetrating from the front surface to the back surface in the thickness direction. Specifically, a rectangular area surrounded by two adjacent notches 17 is cut out from the elastic sheet 10 (see FIGS. 6(d) and 7(d)). This results in an elastic sheet 10a having a plurality of elongated through-holes 12 formed therein, and a plurality of elastic sheet pieces 10b cut out from the elastic sheet 10. In this embodiment, a total of 11 elongated through-holes 12 are formed from the 22 notches provided on each surface of the elastic sheet 11 in the thickness direction. In the through-hole forming step, the elastic sheet piece 10b is preferably cut out in the thickness direction so as to pass through the apex of the generally V-shaped cross section of the incision 17 on the front surface in the thickness direction and the apex of the generally V-shaped cross section of the incision 17 on the back surface opposite the incision 17 (see FIG. 7(d)). By cutting out in this manner, an elastic sheet body 10a is formed, which comprises an elastic sheet 11a having a tapered portion 15 formed on the edge of the opening on the front side of the elongated through-hole 12, and a high-lubrication layer 16 having a tapered portion 16a that covers the tapered portion 15. Furthermore, the elastic sheet piece 10b thus cut out from the elastic sheet body 10 comprises an elastic sheet piece 11b having a tapered portion 15 on the edge of the surface facing the insertion direction (downward in FIG. 7), and a high-lubrication layer 16 having a tapered portion 16a that covers the tapered portion 15.

[0036] (4) Thermally Conductive Film Arrangement Step (S130) This step is a step of arranging a thermally conductive film 20 on the front surface of the elastic sheet 10 so as to preferably cover all of the elongated through holes 12 (see FIG. 8(f)). However, the thermally conductive film 20 may be arranged so as to cover some of the multiple elongated through holes 12. In that case, multiple thermally conductive films 20 may be used to cover all of the elongated through holes 12. This point also applies to the same step in the following embodiments and modified examples.

[0037] (5) Elastic sheet piece insertion process (S140) This process involves inserting the elastic sheet piece 10b into the elongated through hole 12 from above the thermally conductive film 20 to expose the thermally conductive film 20 from the back surface (see Figures 8(g) and (h)).

[0038] 8, a part of the opening of the elongated through-hole 12 (here, one short side 13 of the opening) is connected to the elastic sheet piece 10b, and the elastic sheet piece 10b is rotated about the short side 13, which functions as a rotation axis, to make the elastic sheet piece 10b detachable from the elongated through-hole 12. In other words, when forming the elongated through-hole 12 in the elastic sheet 10, the elastic sheet piece 10b is not completely separated from the elongated through-hole 12, but is cut so that only the short side 13 remains.

[0039] By connecting the elastic sheet piece 10b to the short side 13 of the elongated through hole 12 in this manner, the thermally conductive member 1 can be manufactured as follows. The through hole forming step (S120) described above can be a step of forming the elongated through hole 12 and rotating the elastic sheet piece 10b that connects to a portion of the opening (short side 13) of the elongated through hole 12 to retract it from the elongated through hole 12. The thermally conductive film arranging step (S130) described above can be a step of arranging the thermally conductive film 20 on the front surface of the elastic sheet body 10 in a state in which the elastic sheet piece 10b has been rotated outward from the elastic sheet body 10a, so as to cover the elongated through hole 12. Furthermore, the elastic sheet piece inserting step (S140) described above can be a step of rotating the elastic sheet piece 10b toward the elongated through hole 12 and inserting it into the elongated through hole 12 (see arrow E).

[0040] In the heat conduction member 1 thus completed, the short side 14 at the tip of the elastic sheet piece 10b is in the form of a notch, and the opposite short side 13 is connected to the elastic sheet 10a and is not notched.

[0041] Fig. 9 is a perspective view for explaining a modification of the manufacturing method of Fig. 8. In Fig. 4, the manufacturing process is explained for only a portion of region B, but in Fig. 9, the manufacturing process is explained for the entire region of the heat conduction member.

[0042] The manufacturing method according to this modification differs from the previously described manufacturing method (see FIG. 8 ) in that the elastic sheet pieces 10b are completely separated from the elongated through holes 12. Therefore, the manufacturing method according to this modification is as follows. First, similar to the previously described manufacturing method (see FIGS. 6 and 7 ), an edge processing step (S100) and a high-lubricity layer forming step (S110) are performed to form the elastic sheet body 10. Next, in the through hole forming step (S120), elongated through holes 12 are formed in the elastic sheet body 10 (see FIG. 9( e )). At this time, the elastic sheet pieces 10b are completely separated from the elongated through holes 12. As a result, an elastic sheet body 10a is formed in which tapered portions 15, 16a are formed on the edges of the openings on the front side of the elongated through holes 12. Furthermore, the elastic sheet pieces 10b have tapered portions 15, 16a on the edges of the surface facing the insertion direction. Then, in a heat conductive film arrangement step (S130), a heat conductive film 20 is arranged on the front surface of the elastic sheet 10a with the elongated through holes 12 formed therein, preferably so as to cover all of the elongated through holes 12 (see FIG. 9(f)). Finally, in an elastic sheet piece insertion step (S140), an elastic sheet piece 10b is inserted from above the heat conductive film 20 toward the elongated through holes 12 (see FIGS. 9(g) and 9(h)).

[0043] In the heat conducting member 1 thus completed, the short side 14 on the tip side of the elastic sheet piece 10b and the short side 13 on the opposite side thereof are in the form of a notch.

[0044] FIG. 10 is an enlarged view of a modified example of the heat conducting member, taken in the same direction as part B of FIG.

[0045] In this modification, the heat conduction member 1 has a structure similar to the heat conduction member 1 described above (see FIG. 3 ), but differs from the heat conduction member 1 described above in that it does not include a tapered portion 15 or a curved portion. That is, in this modification, the high-lubrication layer 16 does not include a tapered portion 16 a, and is laminated on both sides of the elastic sheet 11 in the thickness direction. Also, in this modification, the heat conduction film 20 does not include a tapered portion 21, and instead extends in a serpentine pattern in a predetermined direction within the sheet plane, perpendicular to the thickness direction of the elastic sheet 10, while alternately exposed on the front and back surfaces in the thickness direction of the elastic sheet 10. The heat conduction member 1 configured in this manner also achieves the same effects as the heat conduction member 1 described above. Note that the heat conduction member 1 according to this modification has the same configuration as the heat conduction member 1 described above (see FIG. 3 ) except for the absence of the tapered portions 15, 16 a, and 21, and therefore detailed description thereof will be omitted.

[0046] The thermal conduction member 1 according to this modification can be manufactured by omitting the edge processing step (S100) in the above-described method for manufacturing a thermal conduction member (see FIG. 5 ) and by performing the high-slip layer forming step (S110), the through-hole forming step (S120), the thermally conductive film arranging step (S130), and the elastic sheet piece inserting step (S140). That is, in the through-hole forming step (S120), an elastic sheet 10a is formed having a plurality of elongated through-holes 12 that do not have tapered portions 15 on the edges of the openings. In this case, the elastic sheet piece 10b cut from the elastic sheet 10 is a substantially rectangular parallelepiped member that does not have tapered portions 15 on the edges of the surface facing the insertion direction. Then, in a heat conductive film arrangement step (S130), the heat conductive film 20 is arranged on the front surface of the elastic sheet 10, and in an elastic sheet piece insertion step (S140), the elastic sheet piece 10b is inserted into the elongated through hole 12 from above the heat conductive film 20 to expose the heat conductive film 20 from the back surface, thereby manufacturing the heat conductive member 1. With this heat conductive member 1, even if the elastic sheet 11 does not have a tapered portion 15 or a curved portion at the edge that contacts the heat conductive film 20 and the edge has a substantially right-angled shape in cross section, the high lubrication layer 16 covers the elastic sheet 11, thereby reducing friction between the heat conductive film 20 and the elastic sheet 10 and reducing the risk of damage to the heat conductive film 20.

[0047] <Battery> Next, the battery according to this embodiment will be described.

[0048] 11 shows a longitudinal cross-sectional view of a battery equipped with a heat-conducting member, where "longitudinal cross-sectional view" refers to a view cut vertically from the upper opening to the bottom of the battery housing interior.

[0049] In the battery 40 according to this embodiment, the heat source is one or more battery cells 30. The cooling member is a housing 41 that houses the battery cells 30. The thermally conductive member 1 described above is interposed between the battery cells 30 and the housing 41. The structure of the battery 40 will be described below.

[0050] In this embodiment, the battery 40 is, for example, a battery for an electric vehicle and includes a plurality of battery cells 30. A suitable example of the battery 40 is a lithium-ion battery. The battery 40 includes a housing 41 with a bottom that is open on one side. The housing 41 is preferably made of aluminum or an aluminum-based alloy. The battery cells 30 are disposed inside the housing 41 at an interior 44 thereof. Electrodes (not shown) protrude from the upper portions of the battery cells 30. The battery cells 30 are preferably tightly attached to one another within the housing 41 by applying compressive force from both sides using screws or the like (not shown). The bottom 42 of the housing 41 is provided with one or more water-cooling pipes 43 for flowing cooling water 45. The battery cells 30 are disposed within the housing 41 with the thermally conductive member 1 sandwiched between them and the bottom 42 (an example of a cooling member) that constitutes a part of the housing 41.

[0051] In the battery 40 having the above structure, heat is transferred from the battery cells 30 to the housing 41 through the thermally conductive member 1, and the heat is effectively removed by water cooling. The cooling water 45 may be interpreted as a "cooling medium" or a "coolant." Liquid nitrogen or an organic solvent such as ethanol may be used instead of the cooling water 45.

[0052] When the battery cells 30 are set in the housing 41 (see FIG. 11 ), the heat conduction member 1 is compressed in the thickness direction of the heat conduction member 1 between the battery cells 30 and the bottom 42 (part of the housing 41) that has the water-cooling pipes 43. As a result, heat from the battery cells 30 is easily conducted to the heat conduction film 20, the bottom 42, the water-cooling pipes 43, and the cooling water 45.

[0053] FIG. 12 shows a cross-sectional view of a battery cell placed horizontally on a heat-conducting member with its side surface in contact with the heat-conducting member, a partially enlarged view thereof, and a partially cross-sectional view of the battery cell when it expands during charging and discharging.

[0054] In the above-described embodiment, the battery cell 30 is vertically oriented with the thermally conductive member 1 in contact with its lower end. However, the structure and arrangement of the battery cell are not limited to this. As shown in FIG. 12 , the battery cell 31 may be arranged so that the side of the battery cell 31, which contains battery fluid sealed in a pouch, is in contact with the thermally conductive film 20 of the thermally conductive member 1. The temperature of the battery cell 31 rises during charging and discharging. If the battery cell 31 container itself is made of a flexible material, the battery cell 31 may swell, particularly at its side. Even in such a case, as shown in FIG. 12 , the thermally conductive member 1 can deform to fit the shape of the outer surface of the battery cell 31, thereby maintaining high heat dissipation performance during charging and discharging.

[0055] (Other Embodiments) As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these and can be practiced in various modifications.

[0056] Furthermore, the high-lubricity layer 16 is not limited to being a laminate of a resin film. For example, the high-lubricity layer 16 may be formed by applying a gloss coating to at least one surface of the elastic sheet 11 in the thickness direction, or by polishing at least one surface of the elastic sheet 11 in the thickness direction to a mirror finish by buffing.

[0057] The thermally conductive member 1 is preferably manufactured without, for example, an adhesive layer between the thermally conductive film 20 and the high-lubricity layer 16. The shape of the elastic sheet 10 is not particularly limited, and may be, for example, elliptical, trapezoidal, circular, polygonal, or other shape, as long as it can hold the thermally conductive film 20 so that it is exposed at a predetermined interval on at least the surface facing the battery cells 30, 31 and the surface facing the bottom 42. The elongated through-holes 12 are merely one example of through-holes, and through-holes that are not elongated in plan view may also be used. In the above-described manufacturing process, the high-lubricity layer forming step (S110) may be performed before the edge processing step (S100).

[0058] The heat source includes not only the battery cells 30 and 31 but also any object that generates heat, such as a circuit board or the main body of an electronic device. For example, the heat source may be an electronic component such as a capacitor or an IC chip. The thermally conductive member 1 may also be disposed in a structure other than the battery 40, such as an electronic device, a home appliance, or a power generation device.

[0059] The present invention can be used in the field of promoting heat conduction from a heat source to a cooling member that is disposed between the heat source and the cooling member that is at a lower temperature than the heat source.

Claims

1. A thermally conductive member that is interposed between a heat source and a cooling member to transfer heat from the heat source to the cooling member, an elastic sheet body including an elastic sheet that is elastically deformable at least in a thickness direction, and a high-slip layer that is formed on at least one surface of the elastic sheet in the thickness direction and has a higher slipperiness than the elastic sheet; a thermally conductive film that is alternately exposed on a front surface and a back surface of the elastic sheet in a thickness direction and that runs in a meandering manner in a predetermined direction within the sheet surface at a right angle to the thickness direction of the elastic sheet; Equipped with the elastic sheet has a tapered or curved portion at an edge in contact with the thermally conductive film, A heat conductive member characterized in that the high-lubricity layer covers the tapered portion or the curved portion.

2. 2. The heat conductive member according to claim 1, wherein the high-lubricity layer is formed on both sides of the elastic sheet in the thickness direction.

3. 3. The heat conductive member according to claim 1, wherein the high-lubricity layer is a resin film.

4. 4. The heat conductive member according to claim 1, wherein the elastic sheet is a foam sheet.

5. A method for producing the heat conductive member according to any one of claims 1 to 4, comprising the steps of: a high-lubrication layer forming step of forming the high-lubrication layer on at least one surface of the elastic sheet in the thickness direction; a through-hole forming step of forming a plurality of through-holes at predetermined intervals in the elastic sheet body, the through-holes penetrating from the front surface to the back surface in the thickness direction; a thermally conductive film arranging step of arranging the thermally conductive film on the front surface of the elastic sheet so as to cover the through-hole; an elastic sheet piece insertion step of inserting an elastic sheet piece into the through hole from above the thermally conductive film to expose the thermally conductive film from the rear surface; Including, A method for manufacturing a heat conductive member, comprising the steps of: prior to the high-slip layer forming step, carrying out an edge processing step of forming a tapered or curved portion on the edge of the elastic sheet that contacts the heat conductive film.

6. 6. The method for producing a heat conductive member according to claim 5, wherein the high-lubricity layer forming step is a step of forming the high-lubricity layer on both sides of the elastic sheet in a thickness direction.

7. 7. The method for producing a heat conductive member according to claim 5, wherein the high-slip layer forming step is a step of laminating a resin film on at least one surface in a thickness direction of the elastic sheet.

8. the through hole forming step is a step of forming the through hole and rotating the elastic sheet piece connected to a part of the opening of the through hole to move it away from the through hole, 8. The method for manufacturing a heat conductive member according to claim 5, wherein the elastic sheet piece inserting step is a step of rotating the elastic sheet piece toward the through hole and inserting it into the through hole.

9. A battery characterized in that the heat source is one or more battery cells, the cooling member is a housing containing the battery cells, and a thermal conduction member described in any one of claims 1 to 4 is interposed between the battery cells and the housing.