Multilayer insulation material and method for manufacturing the same

Abstract

To provide a heat insulating material that can easily suppress manufacturing variations.SOLUTION: A multilayer insulation material includes an insulating layer containing inorganic fibers and silicon dioxide particles, and satisfies at least one of the following conditions (a) and (b). Condition (a): Two or more insulating layers are laminated, and the two or more insulating layers satisfy a relationship in which there is a certain degree of difference in at least one of their thicknesses or mass per unit area. Condition (b): Two or more buffer layers are laminated, and each buffer layer is made of a fiber molded product containing fibers and a binder, or a foam molded product containing a foam, and the two or more buffer layers satisfy a relationship in which there is a certain degree of difference in at least one of their thicknesses or mass per unit area.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multilayer insulation material and a method for manufacturing the same. [Background technology]

[0002] For example, in lithium-ion battery modules installed in electric vehicles such as automobiles and electric vehicles, multiple battery cells are stacked, and dedicated insulating materials are sometimes placed between the cells to prevent direct contact between adjacent cells and to insulate the cells. Furthermore, because each cell expands and contracts due to charging and discharging, such insulating materials can also serve as buffers against expansion and contraction.

[0003] For secondary batteries, which have large expansion and contraction of battery cells during charging and discharging, Non-Patent Document 1, for example, discloses that by using a binder with an adjusted elastic modulus, expansion of the electrodes can be suppressed and cycle characteristics can be improved.

[0004] Furthermore, Patent Document 1 discloses that the elastic body that receives a load from the electrode body of the secondary battery in the stacking direction of the electrode body also plays a role in absorbing stress, and that by specifying the compressive elastic modulus of each member, it is possible to suppress an increase in resistance during high-rate charging and discharging and a decrease in capacity during charging and discharging cycles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-114361 [Non-patent literature]

[0006] [Non-Patent Document 1] Development of binder for Si anode and evaluation of electrode expansion, JSR Corporation, JSR Technical Review No. 125 (March 2018) Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors have clarified that the insulating material disposed between cells of a lithium-ion battery module is prone to product-to-product variations in properties such as thermal insulation and shock absorption, and that manufacturing variations are the primary cause of this. For example, variations in the properties of the insulating material used in a single battery module can lead to uneven loads on each cell, which may affect performance and durability in charge / discharge cycles. Therefore, reducing such manufacturing variations in insulating materials can be an improvement that can contribute not only to the performance of the insulating material itself but also to the performance and durability of the entire lithium-ion battery module.

[0008] An object of one aspect of the present invention is to provide a heat insulating material that is easy to suppress manufacturing variations. [Means for solving the problem]

[0009] One embodiment of the multilayer thermal insulation material according to the present invention includes a thermal insulation layer containing inorganic particles, and satisfies at least one of the following conditions (a) and (b). Condition (a): The heat insulating layer is formed by laminating two or more layers, and the two or more heat insulating layers satisfy at least one of the following relational expressions (a-1) and (a-2). Relational formula (a-1): ((thickness of the thickest insulation layer) - (thickness of the thinnest insulation layer)) / (average thickness of all insulation layers) x 100 ≥ 1.0 [%] Relational formula (a-2): ((mass per unit area of ​​the insulation layer with the largest mass per unit area) - (mass per unit area of ​​the insulation layer with the smallest mass per unit area)) / (average mass per unit area of ​​all insulation layers) x 100 ≥ 1.0 [%] Condition (b): Two or more buffer layers made of a fiber-containing molded body or a foam-containing molded body are laminated, and the two or more buffer layers satisfy at least one of the following relational expressions (b-1) and (b-2). Relational formula (b-1): ((Thickness of the thickest buffer layer) - (Average thickness of the thinnest buffer layer)) / (Average thickness of all buffer layers) × 100 ≥ 1.0 [%] Relational formula (b-2): ((mass per unit area of ​​the buffer layer with the largest mass per unit area) - ((average mass per unit area of ​​the buffer layer with the smallest mass per unit area))) / (average mass per unit area of ​​all buffer layers) × 100 ≥ 1.0 [%] [Effects of the Invention]

[0010] One aspect of the present invention can provide a heat insulating material that can easily suppress manufacturing variations. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of a multilayer insulation material according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II in FIG. [Figure 3] FIG. 3 is a plan view of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 5] FIG. 5 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 6] FIG. 6 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 7] FIG. 7 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 8] FIG. 8 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 9] FIG. 9 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 10] FIG. 10 is a cross-sectional view showing an example of another configuration of the multilayer thermal insulation material. [Figure 11] FIG. 11 is a cross-sectional view showing an example of another configuration of a multilayer thermal insulator. [Figure 12]FIG. 12 is a perspective view showing an example of a lithium ion secondary battery. [Figure 13] FIG. 13 is a partial cross-sectional view of a lithium ion secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail. To facilitate understanding of the description, the same components in each drawing will be denoted by the same reference numerals, and duplicate descriptions will be omitted. The scale of each component in the drawings may differ from the actual scale. In this specification, unless otherwise specified, "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0013] <Multi-layer insulation> A multilayer insulation according to an embodiment of the present invention will be described. FIG. 1 is a perspective view of the multilayer insulation according to this embodiment, FIG. 2 is a cross-sectional view II of FIG. 1, and FIG. 3 is a plan view of FIG. 1. As shown in FIGS. 1 and 2, the multilayer insulation 1 according to this embodiment is a laminate including a thermal insulation layer 10 and a buffer layer 20, and may include a coating layer 30 that covers the thermal insulation layer 10 and the buffer layer 20. The multilayer insulation 1 is formed in a sheet shape. The multilayer insulation 1 may include the thermal insulation layer 10 laminated on the upper surface 20a of the buffer layer 20. The multilayer insulation 1 may be formed as a laminate in which two buffer layers 20A and 20B are laminated. As shown in FIG. 3, the multilayer insulation 1 is formed in a substantially rectangular shape in plan view. The multilayer insulation 1 may be formed of only the thermal insulation layer 10, or may be formed of the thermal insulation layer 10 and the buffer layer 20.

[0014] In this specification, the thickness direction (vertical direction) of the multilayer insulation 1 is referred to as the Z-axis direction, and the lateral direction (horizontal direction) perpendicular to the thickness direction is referred to as the X-axis direction and the Y-axis direction. The insulating layer 10 side of the Z-axis direction is referred to as the +Z-axis direction, and the buffer layer 20 side is referred to as the -Z-axis direction. In the following explanation, for convenience of explanation, the +Z-axis direction will be referred to as up or upward, and the -Z-axis direction will be referred to as down or downward, but this does not represent a universal up-down relationship.

[0015] The present inventors noticed that insulation materials placed between cells in lithium-ion battery modules are prone to product-to-product variations in their insulation and cushioning properties, with manufacturing variations being the primary cause. After extensive research into ways to reduce this variation, the inventors discovered that managing the insulation material's "thickness" and "mass per unit area" as indicators, and furthermore, because it is difficult to strictly uniformize the insulation material's physical properties during the manufacturing process, it is necessary to find a way to reduce the product-to-product variations in the insulation material's properties even if the insulation material's physical properties are somewhat uneven. The inventors then discovered that by stacking multiple insulation layers 10 and buffer layers 20 to produce a multilayer insulation material, and combining insulation layers and buffer layers that have certain differences in "thickness" and "mass per unit area," it is possible to achieve a balance between the layers and reduce the product-to-product variations in the insulation material.

[0016] The heat insulating layer 10, the buffer layer 20, the covering layer 30, and the method for manufacturing the multilayer thermal insulation material 1 will be described in detail below.

[0017] (insulating layer) The heat insulating layer 10 contains inorganic particles, is formed in a sheet shape, and has the property of making it difficult for heat transferred to the multilayer thermal insulation material 1 to be transferred in the thickness direction, that is, has heat insulating properties.

[0018] The type of inorganic particles contained in the heat insulating layer 10 is not particularly limited, and examples thereof include silicon dioxide (silica), titanium oxide, silicon carbide, ilmenite (FeTiO), zirconium silicate, iron(III) and iron(II) oxides (wüstite (FeO), magnetite (FeO), and hematite (FeO)), chromium dioxide, zirconium oxide, manganese dioxide, zirconia sol, titania sol, silica sol, alumina sol, bentonite, and kaolin. The heat insulating layer 10 may contain one type of inorganic particle or two or more types of inorganic particles. In particular, the inorganic particles are preferably inorganic particles that can suppress thermal radiation, more specifically, inorganic particles that have an absorption peak in the infrared region. The absorption peak in the infrared region can be measured using an infrared spectrophotometer. The inorganic particles may also function as a binder to bind inorganic fibers together.

[0019] When the inorganic particles contained in the thermal insulating layer 10 are silicon dioxide particles, examples of the silicon dioxide particles include dry silica produced by a dry method and wet silica produced by a wet method. Examples of dry silica include fumed silica (hydrophilic fumed silica and hydrophobic fumed silica), and examples of wet silica include precipitated silica, gel silica, colloidal silica, and silica gel. Examples of colloidal silica include anionic colloidal silica and cationic colloidal silica. It is preferable to use silica aerogel or silica xerogel, which have extremely low density. Silica aerogel is a silica gel with a high void ratio to volume, typically 90% or more, and a porous structure of several tens of nanometers. Silica aerogel has low heat transfer due to conduction in the solid portion and hinders the movement of air molecules inside, resulting in low gas conduction and convection and low thermal conductivity. The heat insulating layer 10 may contain one type of silicon dioxide particles, or may contain two or more types of silicon dioxide particles.

[0020] The content of inorganic particles in the thermal insulation layer 10 is not particularly limited and is usually 50% to 100% by mass, but is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95.5% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and particularly preferably 85% by mass or less. If the content of inorganic particles is within the above range, it becomes easier to ensure the thermal resistance of the multilayer thermal insulation material 1 and also makes it easier to manufacture the thermal insulation layer 10.

[0021] The heat insulating layer 10 is a layer containing inorganic particles, and preferably contains fibers in addition to the inorganic particles. The type of fibers contained in the heat insulating layer 10 is not particularly limited, but can be classified into inorganic fibers and organic fibers.

[0022] Specific examples of inorganic fibers include silica fiber, glass fiber, alumina fiber, silica-alumina fiber, silica-alumina-magnesia fiber, biosoluble inorganic fiber, glass fiber, zirconia fiber, alkaline earth silicate fiber, alkaline earth silicate (AES) fiber, glass wool, rock wool, and basalt fiber. Specific examples of organic fibers include aramid fiber, polyester fiber, polyethylene fiber, polypropylene fiber, polyvinyl chloride fiber, fluorinated resin fiber, nylon fiber, rayon fiber, acrylic fiber, and polyolefin fiber. When the insulating layer 10 contains inorganic fibers, its heat resistance is improved. When the insulating layer 10 contains organic fibers, its cushioning properties and durability against repeated pressure fatigue are improved. The insulating layer 10 may contain one type of fiber or two or more types of fibers.

[0023] The fiber content of the insulating layer 10 is not particularly limited and is typically 0.5% to 50% by mass, but is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less. If the fiber content is within this range, it becomes easier to ensure the thermal resistance of the multilayer insulating material 1 and also makes it easier to manufacture the insulating layer 10.

[0024] The average fiber length of the fibers contained in the thermal insulation layer 10 is not particularly limited and is usually 0.05 mm to 50 mm, but is preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 2 mm or more, and is preferably 25 mm or less, more preferably 13 mm or less, even more preferably 6 mm or less. If the average fiber length of the fibers is within the above range, the thermal insulation layer 10 can be easily manufactured.

[0025] The average fiber diameter of the fibers contained in the heat insulating layer 10 is not particularly limited and is usually 0.1 μm to 50 μm, but is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 7 μm or more, and is preferably 25 μm or less, more preferably 20 μm or less, even more preferably 15 μm or less. If the average fiber diameter of the fibers is within the above range, the heat insulating layer 10 will easily achieve both heat insulation and mechanical strength.

[0026] The heat insulating layer 10 is a layer containing inorganic particles, but may contain a binder (binding agent) in addition to the inorganic particles. The type of binder contained in the heat insulating layer 10 is not particularly limited, but can be classified into organic binders and inorganic binders. Specific examples of organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, water-soluble polymers, etc. Specific examples of inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, calcium oxide, etc. Using the above-mentioned binders improves shape stability. The heat insulating layer 10 may contain one type of binder or two or more types of binders.

[0027] When the heat insulating layer 10 contains a binder, the content of the binder is not particularly limited and is usually 0.01% by mass to 10% by mass, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. When the binder content is within the above range, the heat insulating layer 10 is likely to have both heat insulating properties and shape stability.

[0028] The heat insulating layer 10 is a layer containing inorganic particles, preferably a layer containing inorganic particles and fibers, and is preferably a molded body formed from a mixture containing inorganic particles and fibers. When the heat insulating layer 10 is a molded body formed from a mixture containing inorganic particles and fibers, the details of the mixing method and molding method of the inorganic particles and fibers will be described later.

[0029] The multilayer insulation material 1 includes an insulating layer 10 containing inorganic particles and satisfies at least one of the above-mentioned conditions (a) and (b). When condition (a) is satisfied, two or more insulating layers 10 are stacked, such as insulating layers 10A and 10B, and at least one of the following relational expressions (a-1) and (a-2) is further satisfied. Relational formula (a-1): ((Thickness of the thickest insulation layer) - (Thickness of the thinnest insulation layer)) / (Average thickness of all insulation layers) x 100 ≥ 1.0% Relational formula (a-2): ((Mass per unit area of ​​the insulation layer with the largest mass per unit area) - (Mass per unit area of ​​the insulation layer with the smallest mass per unit area)) / (Average mass per unit area of ​​all insulation layers) x 100 ≥ 1.0%

[0030] When the multilayer insulation material 1 includes one insulation layer 10, the thickness of the insulation layer 10 is not particularly limited and is usually 0.5 mm to 10 mm, but is preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. If the thickness of the insulation layer 10 is within the above range, insulation properties can be ensured and the multilayer insulation material 1 can be prevented from becoming too large.

[0031] The thickness of the insulating layer 10 can be measured by measuring the cross section of the insulating layer 10 at several points (e.g., 10 points) using a thickness gauge (e.g., Ozaki Seisakusho's digital thickness gauge JAN-257 (measuring probe Φ20)) and then taking the average value of the measured values.

[0032] When the multilayer insulation material 1 is made up of two laminated insulation layers 10, the average thickness of all the insulation layers 10 is not particularly limited and is usually 0.25 mm to 5 mm, but is preferably 0.5 mm or more, more preferably 0.75 mm or more, even more preferably 1 mm or more, and preferably 3.5 mm or less, more preferably 2.5 mm or less, and even more preferably 1.5 mm or less. If the average thickness of the insulation layers 10 is within the above range, the insulation properties of the insulation layers 10 can be ensured and the multilayer insulation material 1 can be prevented from becoming too large.

[0033] When the multilayer insulation material 1 is made up of three laminated insulation layers 10, the average thickness of all the insulation layers 10 is not particularly limited and is usually 0.1 mm to 3.5 mm, but is preferably 0.3 mm or more, more preferably 0.5 mm or more, even more preferably 0.6 mm or more, and preferably 3 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less. If the average thickness of the insulation layers 10 is within the above range, the insulation properties of the insulation layers 10 can be ensured and the multilayer insulation material 1 can be prevented from becoming too large.

[0034] When the multilayer insulation material 1 is made up of four or more laminated insulation layers 10, the average thickness of all the insulation layers 10 is not particularly limited and is usually 0.12 mm to 2.5 mm, but is preferably 0.25 mm or more, more preferably 0.35 mm or more, even more preferably 0.5 mm or more, and preferably 1.8 mm or less, more preferably 1.3 mm or less, and even more preferably 0.8 mm or less. If the average thickness of the insulation layers 10 is within the above range, the insulation properties of the insulation layers 10 can be ensured and the multilayer insulation material 1 can be prevented from becoming too large.

[0035] When the multilayer insulation material 1 satisfies the above-mentioned condition (a), it will satisfy at least one of the above-mentioned relational expressions (a-1) and (a-2), and the value of "((thickness of the thickest insulation layer) - (thickness of the thinnest insulation layer)) / (average thickness of all insulation layers) x 100" is typically 1.0% to 100%, preferably 1.5% or more, more preferably 2.0% or more, even more preferably 3.0% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When the value is within the above range, the selection labor hours in the assembly processing step can be reduced, thereby improving productivity.

[0036] The numerical value of "(thickness of the thickest insulating layer) - (thickness of the thinnest insulating layer)" is usually 0.05 mm to 5 mm, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, and is preferably 4 mm or less, more preferably 3 mm or less, even more preferably 2 mm or less.

[0037] When the multilayer thermal insulation material 1 includes one thermal insulation layer 10, the mass per unit area (basis weight) of the thermal insulation layer 10 is not particularly limited, and is usually 100 g / m 2 ~5000g / m 2 However, preferably 200 g / m 2 More preferably, 250 g / m 2 More preferably, 300 g / m 2 or more, preferably 4000 g / m 2 or less, more preferably 3000 g / m 2 More preferably, 2000 g / m or less 2 When the mass per unit area of ​​the insulating layer 10 is within the above range, the insulating layer 10 can ensure its thermal insulation properties and can prevent the multilayer insulating material 1 from becoming too large. The mass per unit area of ​​the insulating layer 10 is also referred to as the basis weight of the insulating layer 10.

[0038] The mass of the insulating layer 10 can be determined by cutting the insulating layer 10 to any size that fits on an electronic balance, and then measuring it at several points (e.g., 10 points) using a high-precision, high-performance tuning fork electronic balance (e.g., HJS-620JS manufactured by Shinko Denshi Co., Ltd.), and then using the average value of the values ​​measured.

[0039] The mass per unit area is calculated by dividing the mass of the heat insulating layer 10 of any size by the area of ​​the heat insulating layer 10 (mass per unit area (g / m) 2 )=mass(g) / area(m 2 )) can be calculated.

[0040] When the multilayer thermal insulation material 1 is made up of two laminated thermal insulation layers 10, the average mass per unit area of ​​all the thermal insulation layers 10 is not particularly limited, and is usually 50 g / m 2 ~2500g / m 2 However, preferably 100 g / m 2 More preferably, 125 g / m 2 More preferably, 150 g / m 2 or more, preferably 2000 g / m 2 or less, more preferably 1500 g / m 2 More preferably, 1000 g / m or less 2 When the mass per unit area of ​​the heat insulating layer 10 is within the above range, the heat insulating layer 10 can ensure heat insulating properties, and the multilayer heat insulating material 1 can be prevented from becoming large.

[0041] When the multilayer insulation material 1 is made up of three laminated insulation layers 10, the average mass per unit area of ​​all the insulation layers 10 is not particularly limited, and is usually 30 g / m 2 ~1700g / m 2 However, preferably 60 g / m 2 More preferably, 80 g / m 2 More preferably, 100 g / m 2 or more, and preferably 1500 g / m 2 or less, more preferably 1000 g / m 2 or less, more preferably 700 g / m 2When the mass per unit area of ​​the heat insulating layer 10 is within the above range, the heat insulating layer 10 can ensure heat insulating properties, and the multilayer heat insulating material 1 can be prevented from becoming large.

[0042] When the multilayer thermal insulation material 1 is made up of four or more laminated thermal insulation layers 10, the average mass per unit area of ​​all the thermal insulation layers 10 is not particularly limited, and is usually 25 g / m 2 ~1250g / m 2 However, preferably 50 g / m 2 More preferably, 60 g / m 2 More preferably, 75 g / m 2 or more, preferably 1000 g / m 2 or less, more preferably 750 g / m 2 or less, more preferably 500 g / m 2 When the mass per unit area of ​​the heat insulating layer 10 is within the above range, the heat insulating layer 10 can ensure heat insulating properties, and the multilayer heat insulating material 1 can be prevented from becoming large.

[0043] When the multilayer insulation material 1 satisfies the above-mentioned condition (a), it satisfies at least one of the above-mentioned relational expressions (a-1) and (a-2), and the value of "(mass per unit area of ​​the insulation layer with the largest mass per unit area) - (mass per unit area of ​​the insulation layer with the smallest mass per unit area)" is usually 1.0% to 100%, preferably 1.5% or more, more preferably 2.0% or more, even more preferably 3.0% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When the value is within the above range, the selection process man-hours in the assembly processing step can be reduced, thereby improving productivity.

[0044] The value of "(mass per unit area of ​​the insulation layer with the largest mass per unit area) - (mass per unit area of ​​the insulation layer with the smallest mass per unit area)" is usually 1g / m 2 ~2500g / m 2 However, preferably 2 g / m 2 More preferably, 3 g / m 2More preferably, 5 g / m 2 or more, preferably 2000 g / m 2 or less, more preferably 1500 g / m 2 More preferably, 1000 g / m or less 2 The following is the result.

[0045] The thermal conductivity of the insulating layer 10 at 80°C and 2 MPa is not particularly limited, but is preferably 0.010 W / (m·K) or more, more preferably 0.015 W / (m·K) or more, even more preferably 0.020 W / (m·K) or more, and preferably 0.3 W / (m·K) or less, more preferably 0.2 W / (m·K) or less, and even more preferably 0.1 W / (m·K) or less. The thermal conductivity of the insulating layer at 600°C and 2 MPa is preferably 0.010 W / (m·K) or more, more preferably 0.020 W / (m·K) or more, even more preferably 0.030 W / (m·K) or more, and preferably 0.3 W / (m·K) or less, more preferably 0.2 W / (m·K) or less, and even more preferably 0.1 W / (m·K) or less. The method for measuring thermal conductivity will be described in detail below.

[0046] The thermal resistance of the heat insulating layer 10 under conditions of 80°C and 2 MPa is not particularly limited, but is preferably 0.020 m 2 K / W or more, preferably 0.025m 2 K / W or more, more preferably 0.030m 2 K / W or more, preferably 0.1m 2 K / W or less, preferably 0.08m 2 K / W or less, more preferably 0.06m 2 The thermal resistance of the heat insulating layer 10 under conditions of 600°C and 2 MPa is preferably 0.010 m 2 K / W or more, preferably 0.020m 2 K / W or more, more preferably 0.030m 2 K / W or more, preferably 0.3m 2 K / W or less, preferably 0.2m 2 K / W or less, more preferably 0.1m 2·K / W or less. The method for measuring thermal resistance will be described in detail later.

[0047] The thermal conductivity of the heat insulating layer 10 can be measured by the method described in Japanese Industrial Standards JIS A 1412-2:1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulating materials - Part 2: Heat flow meter method (HFM method)."

[0048] The heat flow meter method (HMF method) is a secondary measurement method or comparative measurement method that measures heat transfer characteristics such as thermal conductivity and thermal resistance by comparing a flat thermal insulation material (insulation layer 10) as a test specimen with a standard plate. The detailed measurement procedure and measurement conditions are explained below.

[0049] The thermal insulation layer 10 is cut to a predetermined size (e.g., 20 mm x 20 mm) to prepare a test specimen, and a standard plate, such as an alumina composite material ("RS-100," manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W / (m·K)), is prepared. Next, the first thermocouple, titanium plate, thermal insulation layer 10, titanium plate, second thermocouple, standard plate, and third thermocouple are placed on the lower plate of a pneumatic press in this order from top to bottom, and the test specimen, standard plate, thermocouple, etc. are tightly pressed between the upper and lower plates. The upper and lower plates are then heated to the predetermined measurement temperatures, and the pneumatic press applies a load to the test specimen, etc. to achieve the predetermined measurement pressure.

[0050] The measurement temperatures are, for example, 80°C for the upper plate on the first thermocouple side and 30°C for the lower plate on the third thermocouple side. On the other hand, the measurement temperatures under high temperature conditions are, for example, 600°C for the upper plate on the first thermocouple side and 40°C for the lower plate on the third thermocouple side.

[0051] The measurement pressure can be set to 2 MPa (load: 800 N). Measurement is continued under heating and pressure until the temperature detected by each thermocouple stabilizes, and the thermal conductivity k1 of the thermal insulating layer 10 can be calculated using the following formula (I) from the temperature detected by each thermocouple after the temperature stabilizes, the thickness of the thermal insulating layer 10 when pressurized, the thermal conductivity of the standard plate, and the thickness of the standard plate when pressurized. k1=k2×(L1×ΔT1) / (L2×ΔT2) ···(I) (In the formula, k1 is the thermal conductivity of the insulating layer [W / (m K)], k2 is the thermal conductivity of the standard plate [W / (m K)], L1 is the thickness of the insulating layer when pressed, L2 is the thickness of the standard plate, ΔT1 is the temperature difference between the temperatures of the second and third thermocouples, and ΔT2 is the temperature difference between the temperatures of the first and second thermocouples.)

[0052] The detected temperature being stabilized means that the temperature change over a period of about 10 minutes falls within a predetermined range (for example, within ±0.1° C.).

[0053] The thermal resistance of the heat insulating layer 10 can be calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 using the following formula (II). R1=L1 / k1 (II) (where R1 is the thermal resistance of the insulating layer [m 2 ·K / W], k1 is the thermal conductivity of the insulating layer [W / (m·K)], and L1 is the thickness of the insulating layer under pressure.)

[0054] The compressibility of the heat insulating layer 10 is not particularly limited, but a density of 300 kg / m 3 A high density insulating layer of 300 kg / m or more 3 It can be considered as a low density insulating layer of less than 10 ...

[0055] The thermal insulation layer 10 has a density of 300 kg / m 3 In the case of a high-density insulating layer such as the above, the compressive stress (the value [MPa] obtained by dividing the compressive force [N] by the initial cross-sectional area of ​​the test specimen) when the compressive strain is 25% is usually 1 MPa to 5 MPa, but is preferably 1.3 MPa or more, more preferably 1.7 MPa or more, and even more preferably 2.0 MPa or more, and is preferably 4.5 MPa or less, more preferably 4.0 MPa or less, and even more preferably 3.5 MPa or less. The compressive stress can be measured by the same method as that for the buffer layer 20 described below.

[0056] The thermal insulation layer 10 has a density of 300 kg / m 3In the case of the above high density insulating layer, the compressive stress when the compressive strain is 50% is usually 4.0 MPa to 15 MPa, but is preferably 5.0 MPa or more, more preferably 6.0 MPa or more, even more preferably 7.0 MPa or more, and preferably 13 MPa or less, more preferably 11 MPa or less, even more preferably 9.0 MPa or less.

[0057] The thermal insulation layer 10 has a density of 300 kg / m 3 In the case of the above high density insulating layer, the compressive stress when the compressive strain is 70% is usually 10 MPa to 25 MPa, but is preferably 11 MPa or more, more preferably 12 MPa or more, even more preferably 13 MPa or more, and is preferably 23 MPa or less, more preferably 21 MPa or less, even more preferably 19 MPa or less.

[0058] The thermal insulation layer 10 has a density of 300 kg / m 3 In the case of a low-density insulating layer of less than 0.05 MPa, the compressive stress when the compressive strain is 25% is usually 0.05 MPa to 1.0 MPa, but is preferably 0.1 MPa or more, more preferably 0.15 MPa or more, even more preferably 0.20 MPa or more, and is preferably 0.7 MPa or less, more preferably 0.5 MPa or less, even more preferably 0.3 MPa or less.

[0059] The thermal insulation layer 10 has a density of 300 kg / m 3 In the case of the above high density insulating layer, the compressive stress when the compressive strain is 50% is usually 1.0 MPa to 4.0 MPa, but is preferably 1.3 MPa or more, more preferably 1.5 MPa or more, even more preferably 1.7 MPa or more, and is preferably 3.5 MPa or less, more preferably 3.0 MPa or less, even more preferably 2.5 MPa or less.

[0060] The thermal insulation layer 10 has a density of 300 kg / m 3In the case of the above high density insulating layer, the compressive stress when the compressive strain is 70% is usually 4.0 MPa to 10 MPa, but is preferably 4.5 MPa or more, more preferably 5.0 MPa or more, even more preferably 5.5 MPa or more, and is preferably 9.0 MPa or less, more preferably 8.0 MPa or less, even more preferably 7.0 MPa or less.

[0061] The number of heat insulating layers 10 is usually 1 or more, preferably 2 or more, and usually 10 or less, preferably 7 or less, and more preferably 5 or less.

[0062] The heat insulating layer 10 may be bonded to adjacent layers with or without an adhesive or pressure-sensitive adhesive, but is preferably not bonded with an adhesive or pressure-sensitive adhesive. Not using an adhesive or pressure-sensitive adhesive can reduce thermal conductivity compared to when an adhesive or pressure-sensitive adhesive is used.

[0063] The shape of the heat insulating layer 10 is not particularly limited, but examples of shapes when viewed from above include a rectangle (for example, a polygon such as a square), a circle, an ellipse, and the like.

[0064] (buffer layer) The buffer layer 20 is made of a fiber molded body containing fibers (hereinafter sometimes abbreviated as "fiber molded body") or a foam molded body containing foam (hereinafter sometimes abbreviated as "foam molded body"), and is a layer laminated on the buffer layer 20 to compensate for the physical properties and other factors that are insufficient in the insulating layer 10 alone.

[0065] A fiber molding is a molding containing fibers, and the aforementioned heat insulating layer 10 is also preferably a molding formed from a mixture containing inorganic particles and fibers. Therefore, when the heat insulating layer 10 is a molding formed from a mixture containing inorganic particles and fibers, this molding can be distinguished from the fiber molding in the buffer layer 20 by whether or not it contains inorganic particles. That is, the layer containing inorganic particles can be considered to be the heat insulating layer 10, and the layer not containing inorganic particles can be considered to be the buffer layer 20. The fiber molding in the buffer layer 20 is preferably a molding containing fibers but not containing inorganic particles.

[0066] The type of fiber contained in the fiber molded body is not particularly limited, but can be classified into inorganic fibers and organic fibers, as in the thermal insulation layer 10. Specific examples include inorganic fibers such as glass wool and rock wool, and felts made of cellulose fiber, polyester, polypropylene, etc., with inorganic fibers being preferred, and glass wool being particularly preferred. Glass wool is a cured material containing fibers and a thermosetting resin, with the fibers bonded together by the thermosetting resin. It also has the effect of increasing compressive stress and exhibiting a buffering function. The fiber molded body may contain one type of fiber or two or more types of fibers. The fiber assembly form may be any of nonwoven fabric, woven fabric, knitted fabric, etc., but is usually in the form of a nonwoven fabric.

[0067] The fiber content of the fiber molding is not particularly limited and is usually 50% to 99% by mass, but is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less. When the fiber content is within this range, the fiber molding is more likely to exhibit cushioning properties.

[0068] The average fiber length of the fibers contained in the fibrous molded article is not particularly limited and is usually 1 mm to 200 mm, but is preferably 5 mm or more, more preferably 10 mm or more, even more preferably 20 mm or more, and is preferably 175 mm or less, more preferably 150 mm or less, even more preferably 125 mm or less. When the average fiber length of the fibers is within the above range, cushioning properties are easily exhibited.

[0069] The average fiber diameter of the fibers contained in the fiber molded product is not particularly limited and is usually 3 μm to 13 μm, but is preferably 4 μm or more, more preferably 4.5 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 9 μm or less, even more preferably 8 μm or less. When the average fiber diameter of the fibers is within this range, the fiber molded product is likely to have both cushioning properties and low thermal conductivity.

[0070] The fibrous molded product is a molded product containing fibers, and preferably contains a binder in addition to the fibers. The type of binder contained in the fibrous molded product is not particularly limited, but can be classified into organic binders and inorganic binders.

[0071] Specific examples of organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, and water-soluble polymers. Specific examples of inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, and calcium oxide. When the binder is one of those described above, shape stability is improved. The heat insulating layer may contain one type of binder or two or more types of binders.

[0072] The binder content of the fiber molding is not particularly limited and is usually 1% to 50% by mass, but is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less. When the binder content is within the above range, low thermal conductivity and good cushioning properties are achieved.

[0073] The fiber molding is a molding containing fibers, and is preferably a molding obtained by molding a mixture containing fibers and a binder but not containing inorganic particles. Some fibers used for the fiber molding are sold in a state in which a thermosetting resin is dispersed as a binder, and such fibers can be cut into the desired shape and then heated and compressed to form a fiber molding.

[0074] A foamed molded article is a molded article containing a foam, and the material of the foam is usually a resin such as a thermoplastic resin or a thermosetting resin, and the foam can be molded by appropriately adopting a known molding method and its conditions.

[0075] The type of resin of the foam contained in the foam molded body is not particularly limited, but specific examples include foamed foams of polyolefin resins such as polyethylene and polypropylene, polyethylene terephthalate resin, polyvinyl chloride resin (PVC), styrene resins such as polystyrene, polyurethane resins such as polyurethane resin, resol-type phenolic resins such as phenolic ribbon resin (PF), melamine resins such as melamine resin (MF), and epoxy resins such as epoxy resin (EP).

[0076] The cell structure of the foamed molded article may be either closed or open, and can be appropriately selected depending on the desired physical properties, etc.

[0077] The multilayer insulation material 1 includes an insulating layer containing inorganic particles and satisfies at least one of the above-mentioned conditions (a) and (b). If condition (b) is satisfied, two or more buffer layers will be stacked, such as buffer layers 20A and 20B, and at least one of the following relationship formulas (b-1) and (b-2) will be satisfied. Relational formula (b-1): ((Thickness of the thickest buffer layer) - (Average thickness of the thinnest buffer layer)) / (Average thickness of all buffer layers) × 100 ≥ 1.0 [%] Relational formula (b-2): ((mass per unit area of ​​the buffer layer with the largest mass per unit area) - ((average mass per unit area of ​​the buffer layer with the smallest mass per unit area))) / (average mass per unit area of ​​all buffer layers) × 100 ≥ 1.0 [%]

[0078] When the multilayer insulating material 1 includes one buffer layer 20, the thickness of the buffer layer 20 is not particularly limited and is usually 0.5 mm to 10 mm, but is preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less. When the thickness of the buffer layer 20 is within the above range, it can appropriately buffer the stress generated by battery expansion. The thickness of the buffer layer 20 can be measured by the same method as that for the insulating layer 10, for example.

[0079] When the multilayer insulating material 1 is made up of two laminated buffer layers 20, the average thickness of all the buffer layers 20 is not particularly limited and is usually 0.25 mm to 5 mm, but is preferably 0.5 mm or more, more preferably 0.75 mm or more, even more preferably 1 mm or more, and is preferably 3.5 mm or less, more preferably 3 mm or less, and even more preferably 2.5 mm or less. When the average thickness of the buffer layers 20 is within the above range, stress generated by battery expansion can be appropriately buffered.

[0080] When the multilayer insulating material 1 is made up of three laminated buffer layers 20, the average thickness of all the buffer layers 20 is not particularly limited and is usually 0.1 mm to 3.5 mm, but is preferably 0.3 mm or more, more preferably 0.5 mm or more, even more preferably 0.7 mm or more, and is preferably 2.5 mm or less, more preferably 2 mm or less, and even more preferably 1.5 mm or less. When the average thickness of the buffer layers 20 is within the above range, stress generated by battery expansion can be appropriately buffered.

[0081] When the multilayer insulating material 1 is made up of four or more laminated buffer layers 20, the average thickness of all the buffer layers 20 is not particularly limited and is usually 0.13 mm to 2.5 mm, but is preferably 0.25 mm or more, more preferably 0.35 mm or more, even more preferably 0.5 mm or more, and is preferably 2 mm or less, more preferably 1.7 mm or less, and even more preferably 1.5 mm or less. When the average thickness of the buffer layers 20 is within the above range, stress generated by battery expansion can be appropriately buffered.

[0082] When the multilayer insulation material 1 satisfies the above-mentioned condition (b), it satisfies at least one of the above-mentioned relational expressions (b-1) and (b-2). The value of "((thickness of the thickest buffer layer) - (thickness of the thinnest buffer layer)) / (average thickness of all buffer layers) x 100" is usually 1.0% to 100%, preferably 1.5% or more, more preferably 2.0% or more, even more preferably 3.0% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When the value is within the above range, the selection man-hours in the assembly processing step can be reduced, thereby improving productivity.

[0083] The value of "(thickness of the thickest buffer layer) - (thickness of the thinnest buffer layer)" is usually 0.05 mm to 5 mm, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, and is preferably 4 mm or less, more preferably 3 mm or less, even more preferably 2 mm or less.

[0084] When the multilayer thermal insulation material 1 includes one buffer layer 20, the mass per unit area of ​​the buffer layer 20 is not particularly limited, and is usually 100 g / m 2 ~5000g / m 2 However, preferably 200 g / m 2 More preferably, 250 g / m 2 More preferably, 300 g / m 2 or more, preferably 4000 g / m 2 or less, more preferably 3000 g / m 2More preferably, 2000 g / m or less 2 When the mass per unit area of ​​the buffer layer 20 is within the above range, the buffer layer 20 can ensure its cushioning properties and prevent the multilayer thermal insulation material 1 from becoming too large. The mass of the buffer layer 20 and the mass per unit area can be measured and calculated in the same manner as for the thermal insulation layer 10, for example.

[0085] When the multilayer thermal insulation material 1 is formed by laminating two buffer layers 20, the average mass per unit area of ​​all the buffer layers 20 is not particularly limited, and is usually 50 g / m 2 ~2500g / m 2 However, preferably 100 g / m 2 More preferably, 125 g / m 2 More preferably, 150 g / m 2 or more, preferably 2000 g / m 2 or less, more preferably 1500 g / m 2 More preferably, 1000 g / m or less 2 When the mass per unit area of ​​the buffer layer 20 is within the above range, the buffer layer 20 can ensure its cushioning properties and the multilayer thermal insulation material 1 can be prevented from becoming large in size.

[0086] When the multilayer thermal insulation material 1 is made up of three stacked buffer layers 20, the average mass per unit area of ​​all the buffer layers 20 is not particularly limited, and is usually 30 g / m 2 ~1700g / m 2 However, preferably 60 g / m 2 More preferably, 80 g / m 2 More preferably, 100 g / m 2 or more, and preferably 1500 g / m 2 or less, more preferably 1000 g / m 2 or less, more preferably 700 g / m 2 When the mass per unit area of ​​the buffer layer 20 is within the above range, the buffer layer 20 can ensure its cushioning properties and the multilayer thermal insulation material 1 can be prevented from becoming large in size.

[0087] When the multilayer thermal insulation material 1 is made up of four or more stacked buffer layers 20, the average mass per unit area of ​​all the buffer layers 20 is not particularly limited, and is usually 25 g / m 2 ~1250g / m 2 However, preferably 50 g / m 2 More preferably, 60 g / m 2 More preferably, 75 g / m 2 or more, preferably 1000 g / m 2 or less, more preferably 750 g / m 2 or less, more preferably 500 g / m 2 When the mass per unit area of ​​the buffer layer 20 is within the above range, the buffer layer 20 can ensure its cushioning properties and the multilayer thermal insulation material 1 can be prevented from becoming large in size.

[0088] When the multilayer insulation material 1 satisfies the above-mentioned condition (b), it satisfies at least one of the above-mentioned relational expressions (b-1) and (b-2), and the value of "(mass per unit area of ​​the buffer layer with the largest mass per unit area) - (mass per unit area of ​​the buffer layer with the smallest mass per unit area)" is usually 1.0% to 100%, preferably 1.5% or more, more preferably 2.0% or more, even more preferably 3.0% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. When the value is within the above range, the selection process man-hours in the assembly processing step can be reduced, thereby improving productivity.

[0089] The value of "(mass per unit area of ​​the buffer layer with the largest mass per unit area) - (mass per unit area of ​​the buffer layer with the smallest mass per unit area)" is usually expressed in 1g / m 2 ~2500g / m 2 However, preferably 2 g / m 2 More preferably, 3 g / m 2 More preferably, 5 g / m 2 or more, preferably 2000 g / m 2 or less, more preferably 1500 g / m 2 More preferably, 1000 g / m or less 2The following is the result.

[0090] The thermal conductivity of the buffer layer 20 is not particularly limited, but is usually higher than that of the thermal insulating layer 10. The thermal conductivity of the buffer layer 20 at 80°C and 2 MPa is not particularly limited, but is preferably 0.030 W / (m·K) or more, more preferably 0.040 W / (m·K) or more, even more preferably 0.050 W / (m·K) or more, and is preferably 0.2 W / (m·K) or less, more preferably 0.25 W / (m·K) or less, and even more preferably 0.1 W / (m·K) or less. The thermal conductivity of the buffer layer at 600°C and 2 MPa is preferably 0.04 W / (m·K) or more, more preferably 0.05 W / (m·K) or more, even more preferably 0.06 W / (m·K) or more, and is preferably 0.30 W / (m·K) or less, more preferably 0.25 W / (m·K) or less, and even more preferably 0.20 W / (m·K) or less. The thermal conductivity may be measured by the same method as that for the heat insulating layer 10.

[0091] The thermal resistance of the buffer layer 20 is not particularly limited, but the thermal conductivity is usually lower than that of the heat insulating layer 10. The thermal resistance of the buffer layer 20 under conditions of 80°C and 2 MPa is not particularly limited, but is preferably 0.020 m 2 K / W or more, preferably 0.025m 2 K / W or more, more preferably 0.03m 2 K / W or more, preferably 0.07m 2 K / W or less, preferably 0.06m 2 K / W or less, more preferably 0.05m 2 The thermal resistance of the buffer layer 20 under conditions of 600°C and 2 MPa is preferably 0.001 m 2 K / W or more, preferably 0.003m 2 K / W or more, more preferably 0.005m 2 K / W or more, preferably 0.1m 2 K / W or less, preferably 0.05m 2 K / W or less, more preferably 0.01 m 2The thermal resistance is equal to or less than 1.5 K / W. The thermal resistance may be measured by the same method as that for the heat insulating layer 10.

[0092] The compression characteristics of the buffer layer 20 are not particularly limited, but the compressive stress when the compressive strain of the buffer layer 20 is 25% is usually 0.1 MPa to 4 MPa, preferably 0.2 MPa or more, more preferably 0.3 MPa or more, even more preferably 0.4 MPa or more, and preferably 3.7 MPa or less, more preferably 3.5 MPa or less, even more preferably 3.3 MPa or less.

[0093] The compressive stress when the compressive strain of the buffer layer 20 is 50% is typically 0.3 MPa to 7 MPa, but is preferably 0.5 MPa or more, more preferably 0.6 MPa or more, even more preferably 0.7 MPa or more, and is preferably 6.5 MPa or less, more preferably 6.0 MPa or less, even more preferably 5.5 MPa or less.

[0094] The compressive stress when the compressive strain of the buffer layer 20 is 70% is usually 2 MPa to 15 MPa, but is preferably 2.3 MPa or more, more preferably 2.5 MPa or more, even more preferably 2.7 MPa or more, and is preferably 14 MPa or less, more preferably 12 MPa or less, even more preferably 10 MPa or less.

[0095] The compressive elastic modulus (yield stress / strain) of the buffer layer 20 is typically 0.5 MPa to 20 MPa, but is preferably 0.7 MPa or more, more preferably 0.9 MPa or more, even more preferably 1.1 MPa or more, and is preferably 18 MPa or less, more preferably 16 MPa or less, even more preferably 14 MPa or less.

[0096] The compressive stress and compressive modulus (yield stress / strain) of the buffer layer 20 can be measured using a precision universal testing machine such as an autograph. Specifically, the buffer layer 20 is cut to a predetermined size to prepare a test specimen, and the test specimen is compressed at a predetermined compression speed (e.g., 0.5 m / min) to measure the compressive stress and displacement, thereby allowing the calculation.

[0097] The number of buffer layers 20 is usually 1 or more, preferably 2 or more, and usually 10 or less, preferably 5 or less, and more preferably 3 or less.

[0098] The buffer layer 20 may be bonded to adjacent layers with or without an adhesive or pressure-sensitive adhesive, but is preferably not bonded with an adhesive or pressure-sensitive adhesive. Not using an adhesive or pressure-sensitive adhesive can reduce thermal conductivity compared to when an adhesive or pressure-sensitive adhesive is used.

[0099] The shape of the buffer layer 20 is not particularly limited, but examples of shapes when viewed from above include a rectangle (for example, a polygon such as a square), a circle, an ellipse, and the like.

[0100] (covering layer) The covering layer 30 is made of a resin film and serves to prevent inorganic particles and the like from falling off the heat insulating layer 10 and to protect the heat insulating layer 10 and the buffer layer 20 .

[0101] The type of resin for the coating layer 30 is not particularly limited, but specific examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide (PI), flame-retardant polycarbonate (PC), breathable porous polyethylene (PE) with a molecular weight of 1 million to 7 million, flame-retardant polyethylene (PE), biaxially oriented nylon film (Ny), etc.

[0102] The thickness of the coating layer 30 is not particularly limited and is usually 0.001 mm to 0.2 mm, but is preferably 0.005 mm or more, more preferably 0.007 mm or more, even more preferably 0.010 mm or more, and preferably 0.15 mm or less, more preferably 0.10 mm or less, and even more preferably 0.050 mm or less. When the thickness of the coating layer 30 is within the above range, both low thermal conductivity and mechanical strength can be achieved. The thickness of the coating layer 30 can be measured in the same way as the heat insulating layer 10.

[0103] The number of coating layers 30 is usually 0 or 1 or more, preferably 2 or more, and usually 5 or less, preferably 4 or less, and more preferably 3 or less. The coating layer 30 is made of a single resin film, and may be folded back and inserted between the heat insulating layer 10 and the buffer layer 20 to form a two-layer coating layer. When folded back in this way, the number of coating layers is considered to be two.

[0104] When the multilayer insulation material 1 is formed by laminating two or more coating layers 30, the two or more coating layers 30 may sandwich and enclose at least one of the insulating layer 10 and the buffer layer 20 in the thickness direction, thereby sealing the gaps between the coating layers 30. The method for sealing the gaps between the coating layers 30 is not particularly limited, but typically includes providing a seal portion on the outer edge of the coating layer 30 and bonding the seal portions between the coating layers 30 together. The method for bonding the seal portions is also not particularly limited, but examples include welding using heat welding, ultrasonic welding, etc., and bonding using an adhesive, pressure-sensitive adhesive, etc. The welding may be performed by directly welding the resin of the coating layer 30, or by providing a separate resin layer for welding and then welding it.

[0105] The covering layer 30 may be bonded to the adjacent insulating layer 10 and / or buffer layer 20 with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that it is not bonded with an adhesive or pressure-sensitive adhesive.

[0106] When the multilayer insulation material 1 is made up of two or more laminated coating layers 30, and the two or more coating layers 30 seal the gaps between the coating layers 30, the coating layers 30 preferably have ventilation holes 33 that connect the gaps to the outside space. By having the ventilation holes 33, shrink packaging can be used as a packaging method.

[0107] The number of ventilation holes 33 in the covering layer 30 is usually 1 or more, preferably 2 or more, and usually 50 or less, preferably 25 or less, and more preferably 10 or less.

[0108] The total open area of ​​the vent holes in the covering layer 30 is typically 0.000079 cm 2 ~10cm 2 However, preferably 0.0001 cm 2 More than 0.005cm, preferably 0.005cm 2 More preferably, 0.01 cm 2 More than 5cm, preferably 2 Less than 4cm, preferably 2 Less than 3cm, more preferably 2 When the total opening area of ​​the ventilation holes 33 in the covering layer 30 is within the above range, the covering layer 30 can suppress the outflow of powder from the heat insulating layer 10 or the buffer layer 20.

[0109] The ventilation holes 33 of the covering layer 30 may be covered with a ventilation membrane. The ventilation membrane usually has an air permeability of 4 cm 3 / (cm 2 s)~500cm 3 / (cm 2 s), but preferably 7 cm 3 / (cm 2 ·s) or more, preferably 10cm 3 / (cm 2 s) or more, more preferably 21 cm 3 / (cm 2 s) or more, preferably 250 cm 3 / (cm 2 s) or less, preferably 200 cm 3 / (cm 2 s) or less, more preferably 100 cm 2 The following is the result.

[0110] (Method of manufacturing multi-layer insulation material) The method for producing the multilayer thermal insulating material 1 is not particularly limited, and it can be produced by appropriately adopting general steps, but typically, a production method including the steps below can be mentioned. Heat insulating layer preparation process: A process of preparing a heat insulating layer containing inorganic particles. Buffer layer preparation step: A step of preparing a buffer layer made of a fiber molded body containing fibers or a foam molded body containing foam. Coating layer preparation process: Coating layer made of resin film is processed Insulation layer thickness measurement process: A process for measuring the thickness of the insulation layer prepared in the insulation layer preparation process. Insulation layer mass measurement process: A process for measuring the mass per unit area of ​​the insulation layer prepared in the insulation layer preparation process. Buffer layer thickness measurement process: A process for measuring the thickness of the buffer layer prepared in the buffer layer preparation process. Buffer layer mass measurement process: A process for measuring the mass per unit area of ​​the buffer layer prepared in the buffer layer preparation process. Insulation layer determination step: A step of determining two or more insulation layers to be used in one multi-layer insulation material based on the thickness and / or mass per unit area from among a group of insulation layers whose thickness and / or mass per unit area have been measured in at least one of the insulation layer thickness measurement step and the insulation layer mass measurement step. Buffer layer determination step: A step of determining two or more buffer layers to be used in one multilayer insulation material based on the thickness and / or mass per unit area from among a group of buffer layers whose thickness and / or mass per unit area have been measured in at least one step selected from the buffer layer thickness measurement step and the buffer layer mass measurement step. Laminating step: a step of laminating a group of constituent layers including two or more heat insulating layers determined in the heat insulating layer determining step and / or two or more buffer layers determined in the buffer layer determining step.

[0111] In addition, the insulating layer preparation process, buffer layer preparation process, insulating layer thickness measurement process, insulating layer mass measurement process, buffer layer thickness measurement process, buffer layer mass measurement process, insulating layer determination process, buffer layer determination process, and stacking process may be processes that are performed simultaneously with other processes in a chronological order, or may be processes that are performed sequentially, as long as they do not refer to previous processes.

[0112] Below, each of the steps of the insulating layer preparation process, buffer layer preparation process, insulating layer thickness measurement process, insulating layer mass measurement process, buffer layer thickness measurement process, buffer layer mass measurement process, insulating layer determination process, buffer layer determination process, and stacking process will be explained in detail.

[0113] The method for preparing the insulating layer in the insulating layer preparation step is not particularly limited, and an existing insulating material may be obtained as the insulating layer, or the insulating layer may be prepared. When the insulating layer 10 is a layer containing inorganic particles and fibers, it can be mixed using a known mixing method such as a wet method or a dry method. An example of a wet method for preparation is a method including the following steps. Mixing process: A process of mixing inorganic particles and fibers in a solvent to obtain a mixed liquid. Coating process: A process of applying the mixture obtained in the mixing process to obtain a coating film. Coating film forming process: A process to form the coating film obtained in the coating process to obtain a heat insulating layer.

[0114] The type of solvent used in the mixing step is not particularly limited, but examples include protic solvents such as acetic acid and water.

[0115] The coating method in the coating step is not particularly limited, and may be a general coating method.

[0116] The method for forming the coating film in the coating film forming step is not particularly limited, but examples thereof include a method in which the coating film is heated and compressed using a heat press.

[0117] The method for preparing the buffer layer in the buffer layer preparation step is not particularly limited, and an existing insulating material or the like may be obtained or prepared as the buffer layer. When the buffer layer 20 is a fiber molded body containing fibers and a binder, a preparation method including the following steps may be used. Precursor preparation process: A process of preparing a precursor in which a binder is dispersed in fibers. Precursor forming process: A process of forming the precursor prepared in the precursor preparation process to obtain a buffer layer.

[0118] As the precursor for the precursor molding step, there are commercially available precursors in which a thermosetting resin is dispersed as a binder in fibers, and such precursors can be obtained.

[0119] The method for molding the precursor in the precursor molding step is not particularly limited, but includes a method in which the precursor is heated and compressed using a heat press.

[0120] The method for measuring the thickness of the insulating layer 10 in the insulating layer thickness measurement step and the method for measuring the thickness of the buffer layer 20 in the buffer layer thickness measurement step are not particularly limited. For example, a method for measuring thickness includes using a Toshiba Corporation X-ray thickness gauge "TOSGAGE-8000A" to measure the amount of transmitted X-rays, calculate the amount of attenuation by the object to be measured, and then back-calculate the thickness. By using this method, the thickness of the plate-shaped insulating layer 10 or buffer layer 20 can be measured non-contact and online. Furthermore, compared to other measurement methods, errors due to water and oil can be reduced.

[0121] The heat insulating layer thickness measuring step and the buffer layer thickness measuring step may be steps that are performed simultaneously in parallel with other steps in a time series, or may be steps that are performed sequentially.

[0122] The method for measuring the mass per unit area of ​​the insulating layer 10 in the insulating layer mass measurement step and the method for measuring the mass per unit area of ​​the buffer layer 20 in the buffer layer mass measurement step are not particularly limited, but examples include a method of automatically measuring the mass using an "NFC-12 combination weigher" manufactured by Ishida Corporation. Using this method not only enables automatic mass measurement but also enables automatic selection of multiple sheets that fall within a specified mass tolerance. Other methods include a method of automatically measuring and sorting the mass using multiple Anritsu Corporation mass inspection autocheckers (KSW6206). Using this method not only enables automatic mass measurement but also enables rapid sorting suitable for mass production.

[0123] In the insulating layer determination step, the method for determining the two or more insulating layers 10 to be used in one multilayer insulating material 1 is not particularly limited, but examples include determining to use a combination of an insulating layer whose thickness and mass per unit area are equal to or greater than a reference value and an insulating layer whose thickness and mass per unit area are equal to or less than a reference value. More specifically, the two or more insulating layers 10 are determined so that the average values ​​of the thickness and / or mass per unit area of ​​the two or more insulating layers 10 fall within a predetermined range of the reference value (preferably within a range of ±15%, more preferably within a range of ±10%, and more preferably within a range of ±5%).

[0124] For example, if you want to sort and classify items into 10 levels including the center value ((1) -25 to -20%, (2) -20 to -15%, (3) -15 to -10%, (4) -10 to -5%, (5) -5 to 0%, (6) 0 to +5%, (7) +5 to +10%, (8) +10 to +15%, (9) +15 to +20%, (10) +20 to +25%), you can line up 10 mass inspection checkweighers in series, set the mass levels (1) to (10) on each unit, and transport the items through each unit. This will allow items with masses within the set range to be sorted. Next, combine the items into the five sorted levels as follows (e.g., (1) + (10), (2) + (9), (3) + (8), (4) + (7), (5) + (6)). By combining them in this way, the tolerance after lamination can be kept within -5% to +5%.

[0125] The method for determining the two or more buffer layers 20 in the buffer layer determining step is not particularly limited, but may be the same as the method in the heat insulating layer determining step.

[0126] The method for laminating the constituent layers in the lamination step is not particularly limited, and the constituent layers may be simply stacked, compressed using a known compression molding method and appropriate conditions, or adjacent layers may be bonded together with an adhesive or pressure-sensitive adhesive. In addition, when gaps between coating layers are sealed by two or more coating layers, bonding the coating layers together is also included in the lamination step.

[0127] The multilayer thermal insulation material 1 according to this embodiment may have other configurations in addition to the configuration shown in Fig. 1. Examples of other configurations of the multilayer thermal insulation material 1 are shown below.

[0128] The multilayer insulation material 1 may be formed by stacking one of the insulating layer 10 and the buffer layer 20 between the other of the insulating layer 10 and the buffer layer 20 in the thickness direction (Z-axis direction) of the multilayer insulation material 1. For example, as shown in FIG. 4, the multilayer insulation material 1 may be provided with a buffer layer 20 on both the upper surface 10a and the lower surface 10b of the insulating layer 10. In this case, both the insulating layer 10 and the buffer layer 20 may be coated with a coating layer 30.

[0129] 5, the multilayer insulation material 1 may be configured with a single buffer layer 20 and an insulation layer 10 consisting of two insulation layers 10A and 10B. In this case, both the insulation layer 10 and the buffer layer 20 may be coated with a coating layer 30.

[0130] 6, the multilayer insulation material 1 may be configured to be composed of a buffer layer 20 and an insulation layer 10 consisting of two insulation layers 10A and 10B, with the insulation layer 10A provided on the lower surface 20b of the buffer layer 20 and the insulation layer 10B provided on the upper surface 20a of the buffer layer 20, with the buffer layer 20 sandwiched between the insulation layers 10. In this case, both the insulation layer 10 and the buffer layer 20 may be coated with the coating layer 30.

[0131] The multilayer insulation material 1 may be composed of two buffer layers 20A and 20B and two insulating layers 10A and 10B. For example, as shown in Fig. 7, the multilayer insulation material 1 may have an insulating layer 10 composed of two insulating layers 10A and 10B laminated on the upper surface 20a of the buffer layer 20. In this case, both the insulating layer 10 and the buffer layer 20 may be coated with a coating layer 30.

[0132] 8, the multilayer insulation material 1 may have two buffer layers 20A and 20B laminated on the upper surface 10a of one insulation layer 10A, and another insulation layer 10B laminated on the upper surface 20a of the buffer layer 20B. In this case, both the insulation layer 10 and the buffer layer 20 may be coated with the coating layer 30.

[0133] 9, the multilayer insulation material 1 may have two insulating layers 10A and 10B laminated on the upper surface 20a of one buffer layer 20A, and a buffer layer 20B laminated on the upper surface 10a of the insulating layer 10B. In this case, both the insulating layer 10 and the buffer layer 20 may be coated with a coating layer 30.

[0134] In this embodiment, the multilayer insulation 1 may be configured by stacking multiple insulating layers 10 and buffer layers 20 in the thickness direction (Z-axis direction) of the multilayer insulation 1, with the insulating layers 10 and buffer layers 20 stacked alternately. For example, as shown in Fig. 10, the multilayer insulation 1 may be configured in two stages, with each stage consisting of a stack of insulating layers 10 stacked on the upper surface 20a of a buffer layer 20, and may be configured by stacking four layers of buffer layer 20A, insulating layer 10A, buffer layer 20B, and insulating layer 10B in the thickness direction (Z-axis direction) of the multilayer insulation 1.

[0135] In addition, the multilayer insulation material 1 may be constructed by stacking five layers in the thickness direction (Z-axis direction) of the multilayer insulation material 1: buffer layer 20, insulation layer 10, buffer layer 20, insulation layer 10 and buffer layer 20, or by stacking five layers: insulation layer 10, buffer layer 20, insulation layer 10, insulation layer 10 and buffer layer 20.

[0136] In this embodiment, as shown in Figure 11, the multilayer insulation material 1 may have only the insulating layer 10 covered with the covering layer 30. In this case, an adhesive layer 40 is provided between the buffer layer 20 and the covering layer 30. The adhesive layer 40 may be a general adhesive, double-sided tape, or the like used in multilayer insulation materials. When the multilayer insulation material 1 has buffer layers 20 on both the upper and lower surfaces of the insulating layer 10 and only the insulating layer 10 is covered with the covering layer 30, an adhesive layer 40 is provided between each of the buffer layers 20 and the covering layer 30.

[0137] The multilayer insulation according to an embodiment of the present invention is not particularly limited as long as it includes a thermal insulation layer and satisfies at least one of the above-mentioned conditions (a) and (b), but the thermal conductivity of the multilayer insulation under conditions of 80°C and 2 MPa is preferably 0.02 W / (m·K) or more, more preferably 0.03 W / (m·K) or more, even more preferably 0.04 W / (m·K) or more, and preferably 0.2 W / (m·K) or less, more preferably 0.15 W / (m·K) or less, and even more preferably 0.10 W / (m·K) or less. The thermal conductivity can be measured by the same method as for the thermal insulation layer 10.

[0138] The thermal resistance of the multilayer heat insulating material under conditions of 80°C and 2 MPa is not particularly limited, but is preferably 0.01 m 2 K / W or more, preferably 0.02m 2 K / W or more, more preferably 0.03m 2 K / W or more, preferably 0.10 m 2 K / W or less, preferably 0.09m 2 ·K / W or less, more preferably 0.08m 2 The thermal resistance is equal to or less than 1.5 K / W. The thermal resistance may be measured by the same method as that for the heat insulating layer 10.

[0139] The difference between the compressive strain when the compressive stress of the multilayer thermal insulation is 3.45 MPa and the compressive strain when the compressive stress is 0.34 MPa (under the condition of a compression speed of 0.5 mm / min) is preferably 10% or more, more preferably 15% or more, even more preferably 20% or more, and is preferably 60% or less, more preferably 50% or less, even more preferably 40% or less. The difference in compressive strain can be measured by the method described below.

[0140] The uses of the multilayer insulation material according to an embodiment of the present invention are not particularly limited and can be used appropriately for known uses in which insulation materials are used, but it is particularly preferred to use it as an insulation material to be placed between cells of a battery module, more specifically as an insulation material to be placed between cells of a lithium ion battery module.

[0141] The target cells may be any of prismatic cells, laminated cells, and cylindrical cells, and the shape of the multilayer heat insulating material may be appropriately adopted depending on the type of cell.

[0142] In addition, target devices for the batteries include electric vehicles (EVs), hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), portable electronic devices such as mobile terminals, mobile phones and laptops, and wearable devices.

[0143] <Battery module> A case where the multilayer insulating material according to this embodiment is applied to a battery module will be described. The types of batteries in the battery module include lithium ion secondary batteries, nickel-hydrogen secondary batteries, nickel-cadmium secondary batteries, and polymer secondary batteries. In this embodiment, a case where the battery is a lithium ion secondary battery will be described.

[0144] Fig. 12 is a perspective view showing an example of a lithium-ion battery module, and Fig. 13 is a partial cross-sectional view of the battery module. As shown in Fig. 12, a battery module 50 includes a plurality of battery cells 51 (four in Fig. 12), a plurality of multilayer heat insulating materials (hereinafter simply referred to as heat insulating materials) 52, and a housing 53. The plurality of battery cells 51 are arranged in the thickness direction of the battery cells 51 within the housing 53 with the heat insulating materials 52 interposed therebetween.

[0145] The number of battery cells 51 is not particularly limited and can be set appropriately depending on the size of the battery cells 51 and the housing 53, and may be one to three, or five or more.

[0146] As shown in FIG. 13 , the multiple heat insulating materials 52 are each arranged between the multiple battery cells 51 in the thickness direction of the battery cells 51 so as to contact the opposing surfaces 51a of the battery cells 51. The welded portions 52a of the heat insulating materials 52 are arranged so as to contact the inner surface of the housing 53. The heat insulating materials 52 suppress heat conduction between the battery cells 51. The heat insulating material 52 may include a heat insulating layer 521 and a buffer layer 522 stacked in this order, and may also include a covering layer 523 that covers the heat insulating layer 521 and the buffer layer 522. The buffer layer 522 may be composed of two buffer layers 522A and 522B. The covering layer 523 may be formed of a pair of resin films 523A and 523B. The heat insulating layer 521, buffer layer 522 and covering layer 523 are similar to the heat insulating layer 10, buffer layer 20 and covering layer 30 of the multilayer thermal insulation material 1 described above, and therefore details thereof will be omitted.

[0147] In this embodiment, the heat insulating layer 521 is disposed so as to face one battery cell 51 (the battery cell 51 on the right side in the thickness direction in FIG. 13), and the buffer layer 522 is disposed so as to face the other battery cell 51 (the battery cell 51 on the left side in the thickness direction in FIG. 13), but the opposite orientation is also possible. Also, when the heat insulating material 52 has a configuration in which the buffer layers 522 are disposed on both main surfaces of the heat insulating layer 521 as shown in FIG. 4, the buffer layers 522 are disposed so as to face both battery cells 51.

[0148] The housing 53 houses a plurality of battery cells 51 and a heat insulating material 52. The shape of the housing 53 is not particularly limited as long as it can house a plurality of battery cells 51 and a heat insulating material 52, and may have a substantially rectangular parallelepiped shape.

[0149] In the battery module 50, by disposing the insulating material 52 between the battery cells 51, when one battery cell 51 becomes hotter than the other battery cells 51 and expands, the buffer layer of the insulating material 52 is compressed and absorbs the expansion of the one battery cell 51, and the insulating layer of the insulating material 52 is hardly compressed and can maintain its insulating properties, thereby reducing the impact on the other battery cells 51.

[0150] A battery cell 51 that has become hot and expanded, a battery cell 51 that has deteriorated and expanded, or a deteriorated heat insulating material 52 may be replaced with a new battery cell 51 or heat insulating material 52 as appropriate.

[0151] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims. [Example]

[0152] The embodiments will be described in more detail below with reference to examples, but the embodiments are not limited to these examples.

[0153] <Manufacturing of multi-layer insulation materials> [Center value 1] (Insulation layer manufacturing) Hydrophilic fumed silica particles ("AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter: approximately 12 μm, BET specific surface area: 200 m 2 A mixed solution was prepared by mixing 21 parts by mass of hydrophilic fumed silica particles (21 parts by mass of silica particles / g), 4 parts by mass of inorganic glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd., average diameter: 13 μm, average fiber length: 6 mm), and a mixed solvent containing 83 parts by mass of acetic acid and 17 parts by mass of water. The mixed solution contained 21 wt%, 4 wt%, and 75 wt% of hydrophilic fumed silica particles, glass fiber, and mixed solvent, respectively. The resulting mixed solution was applied to a substrate to form a coating film. The coating film was compression-molded into a sheet and then dried at 100°C for 10 minutes. This resulted in a 2.0 mm thick, 740 g / m2 mass per unit area film containing fumed silica particles and glass fiber. 2 The heat insulating layer 1 was obtained and cut to a predetermined size (20 mm x 20 mm). The density of the heat insulating layer 1 was 0.35 g / cm 3The thickness was measured using a feeler gauge (digital thickness gauge JAN-257, probe Φ20, manufactured by Ozaki Manufacturing Co., Ltd.). Additionally, a precision universal testing machine (autograph AGS-5kNX, manufactured by Shimadzu Corporation) was used to measure the compressive stress of the heat insulating layer at 25% strain at a compression rate of 0.5 mm / min, and the 25% compressive stress was 8.2 MPa.

[0154] (Buffer layer manufacturing) Glass wool (uncured wool (mass per unit area 1556g / m 2 ), manufactured by Central Glass Fiber Co., Ltd.) was used in a heat press at 180°C. A spacer was installed so that the gap between the upper and lower plates of the heat press was 3.0 mm, and the glass wool was heated for 10 minutes to thermally cure the resin in the glass wool. A compression-molded sheet with a thickness of 3.0 mm was then used.

[0155] (Manufacturing of multi-layer insulation materials) The buffer layer and the heat insulating layer prepared as described above were laminated to obtain a multilayer heat insulating material.

[0156] [Comparative Example 1-1] At center value 1, the mass per unit area of ​​the glass wool of the buffer layer made at center value 1 is 1788 g / m 2 A multilayer insulation material was produced in the same manner as for center value 1, except that the value was changed to

[0157] [Comparative Example 1-2] At center value 1, the mass per unit area of ​​the glass wool of the buffer layer made at center value 1 is 1324 g / m 2 A multilayer insulation material was produced in the same manner as for center value 1, except that the value was changed to

[0158] [Comparative Example 1-3] For center value 1, a multilayer insulation material was produced in the same manner as for center value 1, except that the thickness of the insulating layer produced for center value 1 was changed to 2.2 mm.

[0159] [Comparative Example 1-4] For center value 1, a multilayer insulation material was produced in the same manner as for center value 1, except that the thickness of the insulating layer produced for center value 1 was changed to 1.8 mm.

[0160] [Center value 2] In the case of the center value 1, a multilayer thermal insulation material was produced in the same manner as in the case of the center value 1, except that the thickness of the buffer layer produced in the case of the center value 1 was changed to 3.0 mm.

[0161] [Comparative Example 2-1] At center value 2, the thickness of the buffer layer was changed to 3.3 mm, and the mass per unit area was increased to 1656 g / m 2 The thickness of the heat insulating layer was changed to 2.2 mm. Other than that, the same procedure as for center value 2 was carried out to produce a multilayer heat insulating material.

[0162] [Comparative Example 2-2] At center value 2, the thickness of the buffer layer was changed to 2.7 mm, and the mass per unit area was increased to 1456 g / m 2 The thickness of the heat insulating layer was changed to 1.8 mm. Other than that, the same procedure as for center value 2 was carried out to produce a multilayer heat insulating material.

[0163] [Center value 3] At center value 1, the cushioning layer produced at center value 1 was not provided, and the insulation layer produced at center value 1 had a basis weight of 540 g / m 2 A multilayer insulation material was produced in the same manner as for center value 1, except that the value was changed to

[0164] [Comparative Example 3-1] In the case of center value 1, a multilayer thermal insulation material was produced in the same manner as in the case of center value 1, except that the buffer layer produced in the case of center value 1 was not provided.

[0165] [Comparative Example 3-2] At center value 3, the insulation layer has a basis weight of 440 g / m 2 A multilayer insulation material was produced in the same manner as for center value 1, except that the value was changed to

[0166] [Example 1] (Insulation layer manufacturing) The heat insulating layer was manufactured in the same manner as for center value 1. (Buffer layer manufacturing) The thickness of the buffer layer made with center value 1 was changed to 1.8 mm, and the mass per unit area was 890 g / m 2 The thickness of the buffer layer fabricated with the center value 1 was changed to 1.8 mm, and the mass per unit area was changed to 665 g / m 2 The buffer layer 2 was fabricated by changing the material to the above.

[0167] (Manufacturing of multi-layer insulation materials) The buffer layer 1, buffer layer 2, and heat insulating layer prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0168] [Example 2] The thickness of the buffer layer 1 produced in Example 1 was changed to 1.6 mm, and the mass per unit area was changed to 780 g / m 2 The thickness of the buffer layer 2 prepared in Example 1 was changed to 2.0 mm, and the mass per unit area was changed to 780 g / m 2 A buffer layer 2 was produced in which the above-mentioned changes were made. Other than that, the same procedures as in Example 1 were carried out to produce a multilayer thermal insulation material.

[0169] [Example 3] The mass per unit area of ​​the buffer layer 1 produced in Example 1 was 825 g / m 2 The mass per unit area of ​​the buffer layer 2 prepared in Example 1 was changed to 734 g / m 2 The buffer layer 2 was produced by changing the above. Otherwise, the same procedure as in Example 1 was carried out to produce a multilayer thermal insulation material.

[0170] [Example 4] (Insulation layer manufacturing) The heat insulating layer was manufactured in the same manner as for center value 1. (Buffer layer manufacturing) The thickness of the buffer layer 1 produced in Example 1 was changed to 1.2 mm, and the mass per unit area was changed to 520 g / m 2Furthermore, the thickness of the buffer layer 1 prepared in Example 1 was changed to 1.2 mm and the mass per unit area was changed to 514 g / m 2 Furthermore, the thickness of the buffer layer 1 prepared in Example 1 was changed to 1.2 mm and the mass per unit area was changed to 519 g / m 2 A buffer layer 3 was fabricated in which the above was changed.

[0171] (Manufacturing of multi-layer insulation materials) The buffer layer 1, buffer layer 2, buffer layer 3 and heat insulating layer prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0172] [Example 5] The thickness of the buffer layer 1 produced in Example 4 was changed to 1.0 mm, and the mass per unit area was changed to 501 g / m 2 The thickness of the buffer layer 2 prepared in Example 4 was changed to 1.5 mm and the mass per unit area to 554 g / m. 2 Furthermore, the buffer layer 2 was fabricated by changing the thickness of the buffer layer 3 fabricated in Example 4 to 1.1 mm and the mass per unit area to 532 g / m. 2 A buffer layer 3 was produced in which the thickness was changed to the above. A multilayer thermal insulation material was produced in the same manner as in Example 4 except for the above.

[0173] [Example 6] (Insulation layer manufacturing) The thickness of the heat insulating layer made with center value 1 was changed to 1.0 mm, and the basis weight was changed to 400 g / m 2 The thickness of the heat insulating layer manufactured with the center value 1 was changed to 1.0 mm, and the basis weight was changed to 350 g / m 2 A heat insulating layer 2 was fabricated by changing the material.

[0174] (Buffer layer manufacturing) At center value 1, the mass per unit area of ​​the buffer layer is 1550 g / m 2 A buffer layer was prepared in the same manner as in the case of center value 1, except that the value was changed to

[0175] (Manufacturing of multi-layer insulation materials) The buffer layer, heat insulating layer 1, and heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0176] [Example 7] (Insulation layer manufacturing) The thickness of the heat insulating layer 1 produced in Example 6 was changed to 0.9 mm, and the mass per unit area was changed to 370 g / m 2 The thickness of the heat insulating layer 2 produced in Example 6 was changed to 1.1 mm, and the mass per unit area was changed to 370 g / m 2 The heat insulating layer 2 was fabricated by changing the

[0177] (Buffer layer manufacturing) The buffer layer was produced in the same manner as in Example 6.

[0178] (Manufacturing of multi-layer insulation materials) The buffer layer, heat insulating layer 1, and heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0179] [Example 8] (Insulation layer manufacturing) The mass per unit area of ​​the heat insulating layer 1 produced in Example 6 was 390 g / m 2 The heat insulating layer 1 was produced by changing the mass per unit area of ​​the heat insulating layer 2 produced in Example 6 to 355 g / m 2 The heat insulating layer 2 was fabricated by changing the

[0180] (Buffer layer manufacturing) The buffer layer was produced in the same manner as in Example 6.

[0181] (Manufacturing of multi-layer insulation materials) The buffer layer, heat insulating layer 1, and heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0182] [Example 9] (Insulation layer manufacturing) The mass per unit area of ​​the heat insulating layer 1 produced in Example 6 was 390 g / m 2A heat insulating layer 2 was also produced in the same manner as in Example 6, except that the heat insulating layer 1 was produced by changing the above.

[0183] (Buffer layer manufacturing) The buffer layer 1 and the buffer layer 2 were produced in the same manner as in Example 1.

[0184] (Manufacturing of multi-layer insulation materials) The buffer layer 1, the buffer layer 2, the heat insulating layer 1 and the heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0185] [Example 10] (Insulation layer manufacturing) The heat insulating layer 1 and the buffer layer 2 were produced in the same manner as in Example 7.

[0186] (Buffer layer manufacturing) The buffer layer 1 and the buffer layer 2 were produced in the same manner as in Example 2.

[0187] (Manufacturing of multi-layer insulation materials) The buffer layer 1, the buffer layer 2, the heat insulating layer 1 and the heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0188] [Example 11] (Insulation layer manufacturing) The heat insulating layers 1 and 2 were produced in the same manner as in Example 8.

[0189] (Buffer layer manufacturing) The buffer layer 1 and the buffer layer 2 were produced in the same manner as in Example 3.

[0190] (Manufacturing of multi-layer insulation materials) The buffer layer 1, the buffer layer 2, the heat insulating layer 1 and the heat insulating layer 2 prepared as described above were laminated in this order to produce a multilayer heat insulating material.

[0191] [Example 12] In Example 9, the buffer layer produced in Example 9 was not provided, and the basis weight of the heat insulating layer 1 produced in Example 9 was 300 g / m 2 and the weight of the insulation layer 2 is changed to 248 g / m2 A multilayer thermal insulating material was produced in the same manner as in Example 9, except for the above change.

[0192] [Example 13] In Example 10, the buffer layer produced in Example 10 was not provided, and the basis weight of the heat insulating layer 2 produced in Example 10 was 270 g / m 2 A multilayer thermal insulation material was produced in the same manner as in Example 10, except for the above change.

[0193] [Example 14] In Example 11, the buffer layer produced in Example 10 was not provided, and the weight of the heat insulating layer 1 produced in Example 11 was 370 g / m 2 and the weight of the insulation layer 2 is changed to 175 g / m 2 A multilayer thermal insulation material was produced in the same manner as in Example 11, except for the above change.

[0194] Tables 1 to 6 show the center values ​​and the configurations and properties of the buffer layer and heat insulating layer of each example and comparative example.

[0195] <Evaluation> The thermal conductivity, thermal resistance and cushioning properties of the multilayer thermal insulating materials of each Example and Comparative Example were measured. The measurement results are shown in Tables 1 to 6.

[0196] (thermal conductivity) Thermal conductivity was measured at 600°C and 2 MPa according to the method described in Japanese Industrial Standard JIS A 1412-2:1999, "Methods for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method (HFM method)." Samples were prepared by cutting the multilayer insulation material into 20 mm x 20 mm pieces. A sample, a reference sample (alumina composite material ("RS-100" manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W / (m·K)), and a titanium plate (thickness: 0.2 mm) were also prepared. Next, thermocouple 1 (sheathed thermocouple K type (SCHS1-0), φ=0.15, Class JIS 1, manufactured by Chino Corporation), titanium plate, multilayer insulation as a test specimen, titanium plate, thermocouple 2 (sheathed thermocouple K type (SCHS1-0), φ=0.15, Class JIS 1, manufactured by Chino Corporation), standard plate, and thermocouple 3 (sheathed thermocouple K type (SCHS1-0), φ=0.15, Class JIS 1, manufactured by Chino Corporation) were sandwiched between the lower plate of a pneumatic press (manufactured by Imoto Machinery Co., Ltd.) in this order from top to bottom, and the multilayer insulation, standard plate, and thermocouple were tightly attached. The upper plate was heated to 600 °C and the lower plate was heated to 40 °C. The load of the press was adjusted to 800 N (equivalent to 2 MPa) and then pressurized. Measurements were continued under heating and pressure until the temperature detected by the thermocouple stabilized. The temperature was defined as being stable when the temperature change was within ±0.1°C after 10 minutes. The thermal conductivity k1 of the multilayer insulation was calculated from the temperature detected by each thermocouple after the temperature had stabilized, the thickness of the multilayer insulation when compressed, and the thermal conductivity and thickness of the standard sample using the following formula (I). k1=k2×(L1×ΔT1) / (L2×ΔT2) ···(I) (In the formula, k1 is the thermal conductivity of the multilayer insulation material [W / (m K)], k2 is the thermal conductivity of the standard plate [W / (m K)], L1 is the thickness of the multilayer insulation material when pressed, L2 is the thickness of the standard plate, ΔT1 is the temperature difference between the temperatures of the second and third thermocouples, and ΔT2 is the temperature difference between the temperatures of the first and second thermocouples.)

[0197] (thermal resistance) The thermal resistance of the multilayer thermal insulation material was calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 using the following formula (II). R1=L1 / k1 (II) (where R1 is the thermal resistance of the insulating layer [m 2 ·K / W], k1 is the thermal conductivity of the insulating layer [W / (m·K)], and L1 is the thickness of the insulating layer under pressure.)

[0198] (buffering property) A compression test was conducted using a precision universal testing machine (Autograph AGS-5kNX, manufactured by Shimadzu Corporation) by compressing the test specimen at a compression rate of 0.5 mm / min, and the compressive strain [%] (compressive displacement / initial thickness of the test specimen) and compressive stress [MPa] were measured. The compression test was conducted so that the compressive stresses were 0.34 MPa and 3.45 MPa. The difference between the compressive strain when the compressive stress was 3.45 MPa and the compressive strain when the compressive stress was 0.34 MPa (displacement range of 0.34 MPa to 3.45 MPa) was calculated using the following formula (III), and this was used to evaluate the cushioning properties. Displacement range from 0.34 MPa to 3.45 MPa [%] = (compressive displacement at 3.45 MPa / initial thickness of specimen) × 100% - (compressive displacement at 0.34 MPa / initial thickness of specimen) × 100% (III)

[0199] [Table 1]

[0200] [Table 2]

[0201] [Table 3]

[0202] [Table 4]

[0203] [Table 5]

[0204] [Table 6]

[0205] As can be seen from Tables 1 to 6, when the thickness and mass per unit area of ​​the insulating layer and the thickness and mass per unit area of ​​the buffer layer satisfy the respective predetermined values, the variations in thermal resistance, thermal conductivity, and buffering properties of the multilayer insulating material of each Example are suppressed, and multilayer insulating materials having similar performance can be manufactured. Therefore, it can be said that the multilayer insulating materials of each Example can exhibit similar performance after being assembled into a nonaqueous electrolyte secondary battery, during use, or when removed.

[0206] The present invention includes, for example, the following aspects. <1> A multilayer insulation material comprising a heat insulating layer containing inorganic particles, and satisfying at least one of the following conditions (a) and (b): Condition (a): The heat insulating layer is formed by laminating two or more layers, and the two or more heat insulating layers satisfy at least one of the following relational expressions (a-1) and (a-2). Relational formula (a-1): ((Thickness of the thickest insulation layer) - (Thickness of the thinnest insulation layer)) / (Average thickness of all insulation layers) x 100 ≥ 1.0% Relational formula (a-2): ((Mass per unit area of ​​the insulation layer with the largest mass per unit area) - (Mass per unit area of ​​the insulation layer with the smallest mass per unit area)) / (Average mass per unit area of ​​all insulation layers) x 100 ≥ 1.0% Condition (b): Two or more buffer layers made of a fiber-containing molded body or a foam-containing molded body are laminated, and the two or more buffer layers satisfy at least one of the following relational expressions (b-1) and (b-2). Relational formula (b-1): ((Thickness of the thickest buffer layer) - (Average thickness of the thinnest buffer layer)) / (Average thickness of all buffer layers) × 100 ≥ 1.0% Relational formula (b-2): ((mass per unit area of ​​the buffer layer with the largest mass per unit area) - ((average mass per unit area of ​​the buffer layer with the smallest mass per unit area))) / (average mass per unit area of ​​all buffer layers) × 100 ≥ 1.0% <2> At least the condition (a) is satisfied, The inorganic particles contained in all the heat insulating layers are made of the same material. <1> The multilayer insulation material according to claim 1. <3> At least the condition (b) is satisfied, The fibers and binders or foams contained in all of the buffer layers are made of the same material. <1> or <2> The multilayer insulation material according to claim 1. <4> The inorganic particles are at least one selected from the group consisting of dry silica and wet silica. <1> ~ <3> The multilayer heat insulating material according to any one of the above. <5> The inorganic particles are at least one selected from the group consisting of silica aerogel and silica xerogel. <1> ~ <4> The multilayer heat insulating material according to any one of the above. <6> At least the condition (b) is satisfied, the fiber molded body contains inorganic fibers as the fibers, The content of the inorganic fibers in the fiber molded body is 50.0% by mass to 99.0% by mass. <1> ~ <5> The multilayer heat insulating material according to any one of the above. <7> Further comprising a coating layer made of a resin film; <1> ~ <6> The multilayer heat insulating material according to any one of the above. <8> The coating layer is a laminate of two or more layers, Two or more of the coating layers sandwich and enclose at least one of the heat insulating layer and the buffer layer in the thickness direction, and seal the gaps between the coating layers. <7> The multilayer insulation material according to claim 1. <9> The covering layer has a vent hole connecting the gap with an external space. <8> The multilayer insulation material according to claim 1. <10> The heat insulating layer and the buffer layer are not bonded to adjacent layers by an adhesive or pressure-sensitive adhesive. <1> ~ <9> The multilayer heat insulating material according to any one of the above. <11> disposed between the cells of the battery module, <1> ~ <10> The multilayer heat insulating material according to any one of the above. <12> A method for manufacturing a multilayer insulation material, comprising the following steps of preparing an insulation layer, at least one of the steps of measuring the insulation layer thickness and the step of measuring the insulation layer mass, the following step of determining the insulation layer, and the following step of laminating. Heat insulating layer preparation process: A process of preparing a heat insulating layer containing inorganic particles. Insulation layer thickness measurement process: A process for measuring the thickness of the insulation layer prepared in the insulation layer preparation process. Insulation layer mass measurement process: A process for measuring the mass per unit area of ​​the insulation layer prepared in the insulation layer preparation process. Insulation layer determination step: A step of determining two or more insulation layers to be used in one multi-layer insulation material based on the thickness and / or mass per unit area from among a group of insulation layers whose thickness and / or mass per unit area have been measured in at least one of the insulation layer thickness measurement step and the insulation layer mass measurement step. Lamination process: A process of laminating a group of constituent layers including two or more heat insulating layers determined in the heat insulating layer determination process. <13> The method further includes the following buffer layer preparation step, at least one of the following buffer layer thickness measurement step and buffer layer mass measurement step, and the following buffer layer determination step, The constituent layer group in the lamination step further includes two or more buffer layers determined in the following buffer layer determination step, <12> A method for producing the multilayer insulation material described in Buffer layer preparation step: A step of preparing a buffer layer made of a fiber molded body containing fibers or a foam molded body containing foam. Buffer layer thickness measurement process: A process for measuring the thickness of the buffer layer prepared in the buffer layer preparation process. Buffer layer mass measurement process: A process for measuring the mass per unit area of ​​the buffer layer prepared in the buffer layer preparation process. Buffer layer determination step: A step of determining two or more buffer layers to be used in one multilayer insulation material based on the thickness and / or mass per unit area from among a group of buffer layers whose thickness and / or mass per unit area have been measured in at least one step selected from the buffer layer thickness measurement step and the buffer layer mass measurement step. <14> A method for manufacturing a multilayer insulation material, comprising the following steps: a heat insulating layer preparation step; a buffer layer preparation step; at least one of the following buffer layer thickness measurement step and buffer layer mass measurement step; a buffer layer determination step; and a lamination step. Heat insulating layer preparation process: A process of preparing a heat insulating layer containing inorganic particles. Buffer layer preparation step: A step of preparing a buffer layer made of a fiber molded body containing fibers or a foam molded body containing foam. Buffer layer thickness measurement process: A process for measuring the thickness of the buffer layer prepared in the buffer layer preparation process. Buffer layer mass measurement process: A process for measuring the mass per unit area of ​​the buffer layer prepared in the buffer layer preparation process. Buffer layer determination step: A step of determining two or more buffer layers to be used in one multilayer insulation material based on the thickness and / or mass per unit area from among a group of buffer layers whose thickness and / or mass per unit area have been measured in at least one step selected from the buffer layer thickness measurement step and the buffer layer mass measurement step. Lamination step: A step of laminating a group of constituent layers including two or more buffer layers determined in the buffer layer determination step. [Explanation of symbols]

[0207] 1. Multi-layer insulation 10, 10A, 10B, 521 Insulation layer 20, 20A, 20B, 522 buffer layer 30, 523 Covering layer 31A, 31B Resin film 32 Seal part 33 Ventilation 40 Adhesive layer 50 Battery Module 51 Battery Cell

Claims

1. A multilayer insulation material comprising a heat insulating layer containing inorganic particles, and satisfying at least one of the following conditions (a) and (b): Condition (a): The heat insulating layer is formed by stacking two or more layers, and the two or more heat insulating layers satisfy at least one of the following relational expressions (a-1) and (a-2). Relational formula (a-1): ((thickness of the thickest heat insulating layer) - (thickness of the thinnest heat insulating layer)) / (average thickness of all heat insulating layers) x 100 ≥ 1.0% Relational formula (a-2): ((mass per unit area of ​​the heat insulating layer with the largest mass per unit area) - (mass per unit area of ​​the heat insulating layer with the smallest mass per unit area)) / (average mass per unit area of ​​all heat insulating layers) x 100 ≥ 1.0% Condition (b): Two or more buffer layers made of a fiber-containing molded article or a foam-containing molded article are laminated, and the two or more buffer layers satisfy at least one of the following relational expressions (b-1) and (b-2). Relational formula (b-1): ((thickness of the thickest buffer layer)−(average thickness of the thinnest buffer layer)) / (average thickness of all buffer layers)×100≧1.0% Relational formula (b-2): ((mass per unit area of ​​the buffer layer with the largest mass per unit area) - ((average mass per unit area of ​​the buffer layer with the smallest mass per unit area)) / (average mass per unit area of ​​all buffer layers) × 100 ≧ 1.0%

2. At least the condition (a) is satisfied, 2. The multilayer insulation material according to claim 1, wherein the inorganic particles contained in all of the insulation layers are made of the same material.

3. At least the condition (b) is satisfied, 2. The multilayer insulation material according to claim 1, wherein the fibers and binders or foams contained in all of the buffer layers are made of the same material.

4. 2. The multilayer insulation material according to claim 1, wherein the inorganic particles are at least one selected from the group consisting of dry silica and wet silica.

5. 2. The multilayer insulation material according to claim 1, wherein the inorganic particles are at least one selected from the group consisting of silica aerogel and silica xerogel.

6. At least the condition (b) is satisfied, the fiber molded body contains inorganic fibers as the fibers, The multilayer insulation material according to claim 1, wherein the content of the inorganic fibers in the fiber molding is 50.0 mass% to 99.0 mass%.

7. The multilayer thermal insulation material according to claim 1, further comprising a coating layer made of a resin film.

8. The coating layer is a laminate of two or more layers, The multilayer insulation material according to claim 7, wherein two or more of the coating layers sandwich and enclose at least one of the insulating layer and the buffer layer in the thickness direction, sealing the gaps between the coating layers.

9. The multilayer insulation material according to claim 8 , wherein the covering layer has a vent hole connecting the gap with an exterior space.

10. 2. The multi-layer insulation material according to claim 1, wherein the insulating layer and the buffer layer are not bonded to adjacent layers by an adhesive or pressure sensitive adhesive.

11. The multilayer insulation material of claim 1 disposed between cells of a battery module.

12. A method for manufacturing a multilayer insulation material, comprising the following steps of preparing an insulation layer, at least one of the steps of measuring the insulation layer thickness and the step of measuring the insulation layer mass, the following step of determining the insulation layer, and the following step of stacking. Heat insulating layer preparation step: a step of preparing a heat insulating layer containing inorganic particles - Heat insulating layer thickness measurement process: A process for measuring the thickness of the heat insulating layer prepared in the heat insulating layer preparation process Insulation layer mass measurement step: A step of measuring the mass per unit area of ​​the insulation layer prepared in the insulation layer preparation step - Insulation layer determination step: A step of determining two or more insulation layers to be used in one multilayer insulation material based on the thickness and / or mass per unit area from a group of insulation layers whose thickness and / or mass per unit area have been measured in at least one of the insulation layer thickness measurement step and the insulation layer mass measurement step. Lamination step: a step of laminating a group of constituent layers including two or more heat insulating layers determined in the heat insulating layer determination step.

13. The method further includes the following buffer layer preparation step, at least one of the following buffer layer thickness measurement step and buffer layer mass measurement step, and the following buffer layer determination step, The method for manufacturing a multilayer thermal insulation material according to claim 12, wherein the group of constituent layers in the laminating step further includes two or more buffer layers determined in the buffer layer determining step described below. Buffer layer preparation step: A step of preparing a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam Buffer layer thickness measurement step: a step of measuring the thickness of the buffer layer prepared in the buffer layer preparation step Buffer layer mass measurement step: A step of measuring the mass per unit area of ​​the buffer layer prepared in the buffer layer preparation step Buffer layer determination step: A step of determining two or more buffer layers to be used in one multilayer thermal insulation material based on the thickness and / or mass per unit area from a group of buffer layers whose thicknesses and / or mass per unit area have been measured in at least one step selected from the buffer layer thickness measurement step and the buffer layer mass measurement step.

14. A method for manufacturing a multilayer insulation material, comprising the following steps: an insulating layer preparation step; a buffer layer preparation step; at least one of the following buffer layer thickness measurement step and buffer layer mass measurement step; a buffer layer determination step; and a lamination step. Heat insulating layer preparation step: a step of preparing a heat insulating layer containing inorganic particles Buffer layer preparation step: A step of preparing a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam Buffer layer thickness measurement step: a step of measuring the thickness of the buffer layer prepared in the buffer layer preparation step Buffer layer mass measurement step: A step of measuring the mass per unit area of ​​the buffer layer prepared in the buffer layer preparation step Buffer layer determination step: A step of determining two or more buffer layers to be used in one multilayer thermal insulation material based on the thickness and / or mass per unit area from a group of buffer layers whose thicknesses and / or mass per unit area have been measured in at least one step selected from the buffer layer thickness measurement step and the buffer layer mass measurement step. Lamination step: a step of laminating a group of constituent layers including two or more buffer layers determined in the buffer layer determination step.

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