Polyurethane, method for producing polyurethane, heat storage material, battery pack, and building material

Abstract

A polyurethane containing a structural unit (A) derived from an aromatic compound having an isocyanate group having an average number of functional groups of 2.1 or more, and a structural unit (B) derived from a polyalkylene ether glycol. According to the present invention, it is possible to provide: a polyurethane for heat storage materials, which has good heat storage properties and heat resistance, excellent moldability, and good shape retention due to heating and cold / heat; a heat storage material containing the polyurethane; and a heat storage molded article.

Description

Technical Field

[0001] The present invention relates to polyurethane, a method for producing polyurethane, a heat storage material, a battery pack and a building material. Background Art

[0002] Polyurethanes include thermoplastic polyurethanes, which soften and melt when heated and then solidify when cooled, and thermosetting polyurethanes, which cure when heated. Both polyurethanes exhibit excellent elasticity, mechanical strength, low-temperature properties, abrasion resistance, weather resistance, and oil resistance. They also offer excellent processability and can be easily formed into various shapes. Therefore, they are used in a wide range of applications, including industrial parts such as rollers and casters, automotive parts such as solid tires and belts, and office automation equipment components such as paper feed rollers and copier rollers. They can also be used in a wide range of sports and leisure products.

[0003] In recent years, materials and thermal storage molded articles containing polyurethane for use as thermal storage materials that have a heat storage function, that is, exhibit minimal shape change in response to external temperature changes, have attracted considerable attention. For example, Patent Document 1 proposes a two-component curable polyurethane resin composition as a coating agent with a heat storage function. The composition comprises a base component (A) containing a urethane prepolymer containing blocked isocyanate groups and a curing agent (B) containing microcapsules for encapsulating the thermal storage material and water.

[0004] Patent Document 2 discloses a polyurethane foam having a permeable layer containing a phase change material within a polyurethane foam base as a polyurethane foam having a heat and cold storage (heat and cold storage) function.

[0005] Patent Document 3 discloses a heat-storage urethane resin sheet-like molded article, which is a molded article in which at least microcapsules for encapsulating a heat storage agent are blended into a specific urethane resin as a heat-storage material, a cold-retaining material, a heat-retaining material, and the like for use in heat-storage panels, electronic equipment components, and the like.

[0006] Patent Document 4 proposes a technique for producing polyurethane by adding a phase change material during the polyurethane production process.

[0007] Patent document 5 discloses a panel-type unit device for heat storage floor heating with heat storage function, which is constructed in the form of a heater in the form of a planar resistive heat emitter and stacked with a heat storage body, assembled in a box-shaped wooden frame with a bottom plate, and connected to the power supply components required for operation and integrated.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-129467

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-1973

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 2009-79115

[0013] Patent Document 4: Japanese Patent Application Laid-Open No. 2020-66738

[0014] Patent Document 5: Japanese Patent Application Laid-Open No. 2000-240958 Summary of the Invention

[0015] Problems to be solved by the invention

[0016] The conventionally known polyurethanes for thermal storage materials, thermal storage materials containing them, and molded articles composed of these materials (thermal storage molded articles) disclosed in Patent Documents 1 to 4 lack sufficient thermal storage performance and are susceptible to shape changes due to heating or cooling. Furthermore, there is room for improvement in heat resistance, and additives with thermal storage functions inevitably extract and separate from the polyurethanes for thermal storage materials. This can lead to poor appearance of the thermal storage molded articles when exposed to heating or cooling.

[0017] Furthermore, the thermal storage floor heating system of Patent Document 5 uses a thermal storage material that cannot retain its shape, so the thermal storage material is filled into a sealed container. This limits the shape and application of the thermal storage material, and there is also the possibility of leakage of the enclosed thermal storage material.

[0018] Therefore, in view of the above-mentioned prior art, the present invention aims to provide, as a first object, a polyurethane for a thermal storage material having excellent thermal storage properties and heat resistance, excellent moldability, and good shape retention properties under heating and cooling, even without containing an additive having a thermal storage function, as well as a thermal storage material and a thermal storage molded article containing the same.

[0019] A second object is to provide a polyurethane having excellent shape retention upon heating, a thermal storage molded article comprising the same, a battery pack, a battery pack, a method for producing a battery pack, a method for using a battery pack, and a composition.

[0020] Furthermore, as a third problem, the problem is to provide: a polyurethane having good heat storage properties and heat resistance, excellent moldability, and good shape retention under heating and cooling, even without containing additives having a heat storage function, a heat storage molded body containing the same, and a heat storage building material and a planar heating appliance having the heat storage molded body.

[0021] Solutions for solving problems

[0022] To solve the aforementioned problems, the present inventors conducted intensive research based on the concept of a polymer skeleton that is non-fluid (solid) by chemical crosslinking and produces crystalline portions in the molecular chains between the crosslinking points. As a result, they discovered that a polyurethane comprising a structural unit (A) derived from an aromatic compound having an average number of functional groups of 2.1 or more and a structural unit (B) derived from a polyalkylene ether glycol can solve the aforementioned problems.

[0023] That is, the present invention provides the following [1] to

[79] .

[0024] [1] A polyurethane comprising: a structural unit (A) derived from an isocyanate; and a structural unit (B) derived from a polyol.

[0025] [2] The polyurethane according to [1] above, wherein the structural unit (A) comprises a structural unit (A) derived from an isocyanate having an average functional group number of 2.1 or more.

[0026] [3] The polyurethane according to [1] or [2] above, wherein the isocyanate of the structural unit (A) comprises an aromatic compound having an isocyanate group.

[0027] [4] The polyurethane according to any one of [1] to [3] above, wherein the structural unit (A) comprises polymethylene polyphenyl polyisocyanate.

[0028] [5] The polyurethane according to any one of [1] to [4] above, wherein the ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B) is 0.4≤(II) / (I)≤1.2.

[0029] [6] The polyurethane according to any one of [1] to [5] above, wherein the structural unit (B) has a linear structure and does not have an unsaturated bond.

[0030] [7] The polyurethane according to any one of [1] to [6] above, wherein the polyol of the structural unit (B) comprises a polyalkylene ether glycol.

[0031] [8] The polyurethane according to any one of [1] to [7] above, wherein the polyol of the structural unit (B) comprises polyethylene glycol.

[0032] [9] The polyurethane according to any one of [1] to [8] above, wherein the number average molecular weight of the polyol of the structural unit (B) is within the range of 1,000 to 10,000, preferably 1,500 to 10,000, more preferably 2,000 to 10,000, further preferably 3,000 to 10,000, and particularly preferably 4,000 to 10,000.

[0033]

[10] The polyurethane according to any one of [1] to [9] above, wherein the melting point of the polyol of the structural unit (B) is 35 to 100°C, preferably 40 to 100°C, more preferably 50 to 100°C, and even more preferably 55 to 100°C.

[0034]

[11] The polyurethane according to any one of [1] to

[10] above, wherein the weight fraction of the structural unit (B) relative to the total weight of the structural units (A) and (B) is 50% by weight or more and 99% by weight or less, preferably 60% by weight or more and 99% by weight or less, more preferably 70% by weight or more and 99% by weight or less, further preferably 80% by weight or more and 99% by weight or less, and particularly preferably 90% by weight or more and 99% by weight or less.

[0035]

[12] The polyurethane according to any one of [1] to

[11] above, further comprising a catalyst (C).

[0036]

[13] The polyurethane according to

[12] above, comprising two or more of the catalysts (C).

[0037]

[14] The polyurethane according to

[12] or

[13] above, wherein the catalyst is an organic catalyst, preferably a base catalyst, more preferably a catalyst comprising at least one selected from an amine catalyst and an imidazole catalyst, and particularly preferably a catalyst comprising at least one selected from triethylenediamine and imidazole.

[0038]

[15] The polyurethane according to any one of

[12] to

[14] above, wherein the catalyst (C) preferably contains 20,000 ppm or less of metal, more preferably 10,000 ppm or less of metal, further preferably 5,000 ppm or less of metal, further preferably 1,000 ppm or less of metal, particularly preferably 500 ppm or less of metal, and particularly preferably 100 ppm or less of metal.

[0039]

[16] The polyurethane according to any one of [1] to

[15] above, which is used for a heat storage material.

[0040]

[17] The polyurethane according to any one of [1] to

[16] above, which exhibits a solid-solid phase transition.

[0041]

[18] The polyurethane according to the above

[17] , wherein the endothermic peak temperature in the solid-solid phase transition when the temperature is increased in differential scanning calorimetry is 30°C or higher and 90°C or lower, preferably 30°C or higher and 80°C or lower, more preferably 30°C or higher and 60°C or lower, and further preferably 50°C or higher and 80°C or lower.

[0042]

[19] The polyurethane according to

[17] or

[18] , wherein the exothermic peak temperature in the solid-solid phase transition during cooling in differential scanning calorimetry is 0°C or higher, preferably 20°C or higher, and more preferably 30°C or higher, and on the other hand, the exothermic peak temperature is 80°C or lower, preferably 60°C or lower, and more preferably 50°C or lower.

[0043]

[20] The polyurethane according to any one of [1] to

[19] above, wherein the polyurethane exhibits a solid-solid phase transition, and the enthalpy in the solid-solid phase transition is 30 J / g or more, preferably 50 J / g or more, and more preferably 70 J / g or more.

[0044]

[21] The polyurethane according to any one of [1] to

[20] above, which is thermosetting.

[0045]

[22] The polyurethane according to any one of [1] to

[21] above, having a density of 1.0 to 10 g / cm 3 .

[0046]

[23] The polyurethane according to any one of [1] to

[22] above, wherein the thermal conductivity is 0.2 to 5.0 W / (m·K), preferably 0.25 to 5.0 W / (m·K).

[0047]

[24] A polyurethane composition for a heat storage material, comprising the polyurethane according to any one of [1] to

[23] above.

[0048]

[25] The polyurethane composition for heat storage material according to the above

[24] , wherein the endothermic peak temperature in the solid-solid phase transition when the temperature is increased in differential scanning calorimetry is 30°C or higher, preferably 50°C or higher, and 90°C or lower, preferably 80°C or lower, and more preferably 60°C or lower.

[0049]

[26] The polyurethane composition for heat storage material according to

[24] or

[25] , wherein the exothermic peak temperature of the solid-solid phase transition during the temperature reduction in differential scanning calorimetry is 0 to 80°C, the endothermic peak temperature of the solid-solid phase transition during the temperature increase in differential scanning calorimetry is 30 to 90°C, and the enthalpy of the solid-solid phase transition is 50 J / g or more.

[0050]

[27] The polyurethane composition for heat storage materials according to any one of

[24] to

[26] , wherein the exothermic peak temperature in the solid-solid phase transition during cooling in differential scanning calorimetry is 0°C or higher, preferably 20°C or higher, more preferably 30°C or higher, and 80°C or lower, preferably 60°C or lower, more preferably 50°C or lower.

[0051]

[28] The polyurethane composition for heat storage material according to any one of

[24] to

[27] above, wherein the exothermic peak temperature in the solid-solid phase transition during temperature reduction in differential scanning calorimetry is 0 to 80°C, the endothermic peak temperature in the solid-solid phase transition during temperature increase in differential scanning calorimetry is 30 to 90°C, and the enthalpy change in the solid-solid phase transition is 30 J / g or more.

[0052]

[29] The polyurethane composition for a thermal storage material according to any one of

[24] to

[28] above, further comprising an antioxidant.

[0053]

[30] The polyurethane composition for a thermal storage material according to

[29] above, wherein the content of the antioxidant is 0.05 to 3% by mass relative to the total amount of the composition.

[0054]

[31] The polyurethane composition for a thermal storage material according to

[29] or

[30] above, wherein the antioxidant is a phenolic antioxidant.

[0055]

[32] The polyurethane composition for a heat storage material according to any one of

[24] to

[31] above, wherein the rate of change ΔH of the enthalpy of the peak derived from the polyurethane for a heat storage material after treatment at 100°C for 200 hours is 10% or less.

[0056]

[33] The polyurethane composition for a heat storage material according to any one of

[24] to

[32] above, further comprising a filler.

[0057]

[34] The polyurethane composition for heat storage material according to any one of

[24] to

[33] above, wherein the content of the filler is 0.1 to 60% by mass, preferably 0.1 to 50% by mass, and more preferably 0.1 to 40% by mass relative to the total amount of the composition.

[0058]

[35] A composition comprising an isocyanate (a) having an average functional group number of 2.1 or more and a polyol (b).

[0059]

[36] The composition according to

[35] above, wherein the isocyanate (a) comprises an aromatic compound having an isocyanate group.

[0060]

[37] The composition according to

[36] above, wherein the aromatic compound comprises polymethylene polyphenyl polyisocyanate.

[0061]

[38] The composition according to any one of

[35] to

[37] above, wherein the ratio of the isocyanate group equivalent (II) of the isocyanate (a) to the hydroxyl group equivalent (I) of the polyol (b) is 0.4≤(II) / (I)≤1.2.

[0062]

[39] The composition according to any one of

[35] to

[38] above, wherein the polyol comprises a polyalkylene ether glycol.

[0063]

[40] The composition according to

[39] , wherein the polyol comprises polyethylene glycol.

[0064]

[41] The composition according to any one of

[35] to

[40] above, wherein the number average molecular weight of the polyol (b) is 1,000 to 10,000, preferably 1,500 to 10,000, more preferably 2,000 to 10,000, further more preferably 3,000 to 10,000, and particularly preferably 4,000 to 10,000.

[0065]

[42] The composition according to any one of

[35] to

[41] above, wherein the melting point of the polyol (b) is 35 to 100°C, preferably 40 to 100°C, more preferably 50 to 100°C, and even more preferably 55 to 100°C.

[0066]

[43] The composition according to any one of

[35] to

[42] above, wherein the weight fraction of the polyol (b) is 50% by weight or more and 99% by weight or less, preferably 60% by weight or more and 99% by weight or less, more preferably 70% by weight or more and 99% by weight or less, further preferably 80% by weight or more and 99% by weight or less, and particularly preferably 90% by weight or more and 99% by weight or less, relative to the total weight of the isocyanate (a) and the polyol (b).

[0067]

[44] The composition according to any one of

[35] to

[43] above, further comprising a catalyst (C).

[0068]

[45] The composition according to

[44] above, comprising two or more of the aforementioned catalysts (C).

[0069]

[46] The composition according to

[44] or

[45] above, wherein the catalyst is an organic compound, preferably a basic compound, more preferably a nitrogen-containing compound, and further preferably at least one selected from triethylenediamine and imidazole.

[0070]

[47] The composition according to any one of

[44] to

[46] above, wherein the catalyst (C) contains less than 20,000 ppm of metal, preferably less than 10,000 ppm of metal, more preferably less than 5,000 ppm of metal, further preferably less than 1,000 ppm of metal, further preferably less than 500 ppm of metal, and particularly preferably less than 100 ppm of metal.

[0071]

[48] ​​The composition according to any one of

[44] to

[47] above, further comprising an antioxidant.

[0072]

[49] The composition according to any one of

[44] to

[48] above, further comprising a filler.

[0073]

[50] The composition according to any one of

[44] to

[49] above, wherein the content of the filler is 0.1 to 60 mass %, preferably 0.1 to 50 mass %, and more preferably 0.1 to 40 mass %, relative to 100 mass % of the composition.

[0074]

[51] A method for producing polyurethane, comprising mixing an aromatic compound having an isocyanate group having an average functional group number of 2.1 or more, a polyalkylene ether glycol, and a catalyst to obtain the polyurethane.

[0075]

[52] A heat storage building material comprising a heat storage material disposed around a heat source, wherein the heat storage material comprises the polyurethane composition for a heat storage material according to any one of

[24] to

[34] .

[0076]

[53] The heat storage building material according to

[52] above, wherein the heat source is a heat medium and a heat medium heat circulation pipe, or an electric heating wire and a heat medium circulation pipe connected to the heat source.

[0077]

[54] The heat storage building material according to

[52] or

[53] above, wherein the heat source is located under the floor or on the wall of the building.

[0078]

[55] The heat storage building material according to any one of

[52] to

[54] above, which is a heat storage building material having a heat storage material arranged around a heat source, wherein the heat storage material includes the heat storage material according to any one of

[24] to

[34] above.

[0079]

[56] A central heating system or heating equipment comprising the heat storage building material described in any one of

[52] to

[55] above.

[0080]

[57] A planar heating appliance comprising a heat storage molded body comprising the polyurethane for heat storage material according to any one of

[24] to

[34] .

[0081]

[58] The planar heating device according to the above-mentioned

[59] further comprises a heating wire, and a heat storage material is contained around the heating wire.

[0082]

[59] A vehicle seat comprising a heat storage molded body comprising the polyurethane for heat storage material according to any one of

[24] to

[34] .

[0083]

[60] The vehicle seat according to the above-mentioned

[59] further comprises a heating wire, and a heat storage material is contained around the heating wire.

[0084]

[61] A battery pack comprising: a plurality of single cells; and a heat storage molded body comprising the polyurethane for heat storage material according to any one of

[24] to

[34] above, the body being in contact with the single cells.

[0085]

[62] The battery pack according to

[61] above, wherein the heat storage material molded body shows an endothermic peak temperature in the range of 30 to 80°C when heated in differential scanning calorimetry, and the distance between any two single cells is 1.0 mm or more, preferably 1.5 mm or more, more preferably 2.0 mm or more, and even more preferably 2.5 mm or more.

[0086]

[63] The battery pack according to

[61] or

[62] above, wherein the single cell is a cylindrical cell.

[0087]

[64] A battery pack comprising the battery pack described in any one of

[61] to

[63] above housed in a housing.

[0088]

[65] The battery pack according to

[64] above, wherein the heat storage molded body has a continuous structure within the shell.

[0089]

[66] The battery pack according to

[64] or

[65] further comprises a heat conducting plate, wherein the heat conducting plate is in contact with the single battery and the heat storage molded body.

[0090]

[67] The battery pack according to any one of

[64] to

[66] above, wherein the heat conductive plate is arranged at the bottom of the heat storage material.

[0091]

[68] A method for manufacturing a battery pack comprising a plurality of single cells arranged in a shell, the method comprising the following steps: heating the shell and at least one of the single cells; and filling the shell with a composition, wherein the composition is any one of the compositions described in

[44] to

[50] .

[0092]

[69] The method for manufacturing a battery pack according to

[68] , comprising the steps of: 3 The F in the formula (I) defined by the minimum value (m) of the distance between the centers of the batteries arranged in the case is adjusted to be 1.5 N or less.

[0093] F = (viscosity of the composition) 0.53 ×(filling volume flow rate) 0.62 / (Minimum distance between multiple batteries placed in the housing) 1.3 ···(I)

[0094]

[70] The method for manufacturing a battery pack according to the above-mentioned

[68] or

[69] comprises the following steps: using a polyol having a viscosity of 1.0 Pa·s or less at 25°C, preferably using a crystalline polyol having a viscosity of 0.8 Pa·s or less at 25°C, more preferably using a polyol having a viscosity of 0.6 Pa·s or less at 25°C, further preferably using a polyol having a viscosity of 0.4 Pa·s or less at 25°C, and particularly preferably using a polyol having a viscosity of 0.2 Pa·s or less at 25°C.

[0095]

[71] The method for manufacturing a battery pack according to any one of

[68] to

[70] above, comprising: the aforementioned composition becomes a phase change material after curing.

[0096]

[72] A method for manufacturing a battery pack according to any one of

[68] to

[71] above, wherein the phase change material has an endothermic peak temperature, and the endothermic peak temperature when the temperature is increased in differential scanning calorimetry is 30 to 90°C, preferably 50 to 80°C.

[0097]

[73] A method for manufacturing a battery pack according to any one of

[68] to

[72] above, wherein the composition is filled at a rate of 50% or more, preferably 60% or more, more preferably 70% or more, and further preferably 80% or more relative to 100% of the height of the battery, and is filled at a rate of 100% or less, preferably 97% or less, more preferably 95% or less, further preferably 90% or less, and particularly preferably 85% or less.

[0098]

[74] A method for manufacturing a battery pack according to any one of

[68] to

[73] above, comprising: adjusting the aforementioned F so that the angle θ1 calculated by any one of the following equations (3) and (4) becomes less than the threshold angle θ2.

[0099] (When 0°≤θ1<3°)

[0100] F = 1.31 × 10 -1 × (angle of the gradient formed by the composition relative to the bottom surface of the battery pack when the composition is filled: θ1) -1.44×10 -2 Formula (3)

[0101] (When θ1≥3°)

[0102] F = 3.93 × 10 -2 × (angle of the gradient formed by the composition relative to the bottom surface of the battery pack when the composition is filled: θ1) -5.02×10 -2 Formula (4)

[0103] The threshold angle θ2 is expressed as arctan(X / Y), where X is the distance between the foot of a perpendicular line drawn from the front end of the nozzle to the bottom surface of the battery pack and the foot of a perpendicular line drawn from the foot of the perpendicular line to the plane bisecting the short side of the battery pack, and Y is the height of the cylindrical battery.

[0104] θ1 is preferably 40° or less, more preferably 35° or less, further preferably 30° or less, further preferably 25° or less, more preferably 20° or less, further preferably 15° or less, and particularly preferably 12° or less.

[0105]

[75] The method for manufacturing a battery pack according to any one of

[68] to

[74] above, comprising the step of heating the composition to a temperature above the melting point of the crystalline polyol.

[0106]

[76] The method for manufacturing a battery pack according to

[75] above, wherein the heating is performed at 20 to 120°C, preferably at 40 to 120°C, and more preferably at 60 to 120°C.

[0107]

[77] The method for manufacturing a battery pack according to any one of

[68] to

[76] , comprising the step of: setting the filling volume flow rate of the composition to 2.0×10 -7 m 3 / s or less, preferably the filling volume flow rate of the composition is 1.0×10 -7 m 3 / s or less, and more preferably, the filling volume flow rate of the composition is 0.5×10 -7 m 3 / s or less, and particularly preferably, the filling volume flow rate of the composition is 0.2×10 -7 m 3 / s or less processes.

[0108]

[78] The method for manufacturing a battery pack according to any one of

[68] to

[77] above, comprising the step of setting the distance between batteries to 1.0 to 4.0 mm, preferably 1.0 to 3.0 mm, and more preferably 1.0 to 2.0 mm.

[0109]

[79] The method for manufacturing a battery pack according to any one of

[68] to

[78] above, wherein the casing is filled with the composition from at least two locations.

[0110] Effects of the Invention

[0111] According to the present invention, there can be provided a polyurethane for a thermal storage material having excellent heat storage properties and heat resistance, excellent moldability, and excellent shape retention properties under heating and cooling, a thermal storage material, and a thermal storage molded article containing the same.

[0112] In addition, it is possible to provide: a polyurethane having good heat storage properties and heat resistance, excellent moldability, and good shape retention under heating and cooling, even without containing additives having a heat storage function, a heat storage molded body containing the same, a battery pack, a battery pack, a method for manufacturing a battery pack, a method for using a battery pack, and a composition.

[0113] Furthermore, it is possible to provide: a polyurethane having good heat storage properties and heat resistance, excellent moldability, and good shape retention under heating and cooling, even without containing an additive having a heat storage function; a heat storage molded body containing the same; and a heat storage building material and a planar heating appliance having the heat storage molded body. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] Figure 1 This is a graph showing the DSC curve at the time of temperature increase in Example 1.

[0115] Figure 2 This is a graph showing the DSC curve during temperature reduction in Example 1.

[0116] Figure 3 This is a diagram showing a building model provided with a thermal storage material in Example 17.

[0117] Figure 4 It is a plan view showing an example of single cells constituting a battery pack.

[0118] Figure 5 for Figure 4 Front view of a single battery.

[0119] Figure 6 for Figure 4 Right side view of a single cell.

[0120] Figure 7 A top view of a battery pack formed by multiple single cells.

[0121] Figure 8 This is a side view schematically showing a state where the side panels are removed from the battery pack.

[0122] Figure 9 is the model used in the simulation.

[0123] Figure 10 A diagram showing a battery pack.

[0124] Figure 11 A snapshot of potting in simulation.

[0125] Figure 12 A cross-sectional view of the battery pack.

[0126] Figure 13 A cross-sectional view of the battery pack.

[0127] Figure 14 This is a plan view of the battery pack. DETAILED DESCRIPTION

[0128] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be implemented in various ways within the scope of its purpose. In addition, when the expression "to" is used in this specification, it is used to include the numerical value or physical value recorded before and after it. In addition, the numerical value or physical value recorded as the upper limit or lower limit is used to include the meaning of the value. In addition, in this specification, "parts by weight" and "parts by mass", "weight %" and "mass %" are essentially the same meaning.

[0129] "Enthalpy" refers to the change in enthalpy during a solid-solid phase transition.

[0130] "Enthalpy of fusion" refers to the enthalpy change in a solid-solid phase transition during temperature increase.

[0131] The "endothermic peak temperature" refers to the peak temperature in the solid-solid phase transition when the temperature is increased in differential scanning calorimetry.

[0132] The "exothermic peak temperature" refers to the peak temperature in the solid-solid phase transition when the temperature is lowered in differential scanning calorimetry.

[0133] "Inter-battery distance" refers to the distance between the outer casings along the line segment connecting the centers of gravity of two adjacent batteries. "Solid-solid phase transition" refers to a phase transition from a solid phase to a non-fluid state. This also includes a phase transition from a solid phase to an intermediate phase between a solid and liquid phase, as long as the phase transition is non-fluid.

[0134] The “structural unit” refers to a structure derived from either isocyanate or polyol in a polymer structure, and does not refer to a single urethane bond.

[0135] The “average number of functional groups” refers to the number of isocyanate groups per one isocyanate compound forming a structural unit.

[0136] [1. Polyurethane]

[0137] [1-1. Polyurethane with specific structure]

[0138] The polyurethane as one embodiment of the present invention (hereinafter also referred to as phase change material) preferably comprises: a structural unit (A) derived from an isocyanate having an average number of functional groups of 2.1 or more, and a structural unit (B) derived from a crystalline polyol. It may further comprise a catalyst described later in [2. Composition]. The polyurethane is characterized by confirming the presence or absence of a peak derived from the structural unit by infrared spectroscopy (ATR method) of a polymer sample. In addition, the polyurethane as one embodiment of the present invention is preferably a polyurethane, characterized in that it comprises: a structural unit (A) derived from an aromatic compound having an isocyanate group having an average number of functional groups of 2.1 or more, and a structural unit (B) derived from a polyalkylene ether glycol, and the polyurethane has an exothermic peak temperature at 0 to 50°C.

[0139] <Isocyanate>

[0140] The isocyanate used to obtain the polyurethane of the present invention is an isocyanate having an average functional group number of 2.1 or more. There are no particular restrictions as long as the isocyanate group has an average functional group number of 2.1 or more, and examples thereof include aliphatic compounds, aromatic compounds (hereinafter sometimes referred to as "aromatic polyisocyanate compounds"), and known polyisocyanate compounds. From the viewpoint of controlling the curing time, the aforementioned isocyanate is preferably an aromatic compound. It should be noted that, with respect to the average functional group number of the isocyanate group, in the case of the pre-reaction isocyanate before obtaining the polyurethane, it can be obtained as follows: end-capping with an alcohol such as dehydrated methanol as a pre-treatment, dissolving in a highly polar deuterated solvent such as deuterated chloroform, and then1 H-NMR, 13 C-NMR was used to determine the result.

[0141] As another method, it can be calculated from the isocyanate (NCO) content according to the following formula: The isocyanate content can be determined by back titration with dibutylamine as specified in JIS-K1603 B method.

[0142] Average number of isocyanate functional groups = NCO content × 4.2 / 1000 × molecular weight

[0143] The average number of isocyanate functional groups in the polyurethane of the present invention after the reaction is determined by measuring the average number of isocyanate functional groups in the polyurethane of the present invention after the reaction. 1 The average number of functional groups was determined by H-NMR. 1 The calculation is performed by assigning the structure by H-NMR. For example, in the case of polymethylene polyphenyl polyisocyanate described below, the calculation is performed from the ratio of the peak area corresponding to the terminal amine to the peak area corresponding to the methylene group.

[0144] From the viewpoint of making the polyurethane obtained by introducing crosslinking points non-fluid (solid), the average number of functional groups of the isocyanate is 2.1 or more, more preferably 2.2 or more, and even more preferably 2.3 or more.

[0145] Examples of the aromatic polyisocyanate compound include polymethylene polyphenyl polyisocyanate (polymeric MDI), an adduct obtained by adding a polyol to xylene diisocyanate (XDI), an adduct obtained by adding a polyol to toluene diisocyanate (2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hereinafter referred to as TDI), and isocyanurate and biuret forms derived from TDI.

[0146] Among these, polymethylene polyphenyl polyisocyanate is more preferable as the aromatic polyisocyanate compound from the viewpoints of high reactivity with crystalline polyols, high curability of the obtained polyurethane, and industrial availability at low cost and in large quantities.

[0147] Furthermore, the aromatic polyisocyanate compound of the present invention may have a structural unit derived from an aromatic compound having a bifunctional diisocyanate group within a range not impairing the physical properties. Examples of the aromatic compound having a bifunctional diisocyanate group include aromatic diisocyanate compounds such as xylene diisocyanate, 4,4'-diphenyl diisocyanate, toluene diisocyanate (2,4-toluene diisocyanate, 2,6-toluene diisocyanate), m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, polymethylene polyphenyl isocyanate, phenylene diisocyanate, and m-tetramethylxylene diisocyanate.

[0148] These may be used alone or in combination of two or more.

[0149] <Crystalline Polyol>

[0150] A crystalline polyol is a hydroxy compound having one or more ether bonds in the main backbone of the molecule. Examples of crystalline polyols include polyalkylene ether glycols. The repeating units in the main backbone can be either saturated hydrocarbons or unsaturated hydrocarbons, or can be linear, branched, or cyclic. From the perspective of improving thermal storage properties, saturated hydrocarbons are preferred, and linear structures are more preferred. Specifically, structural unit (B) preferably has a linear structure, preferably one without unsaturated bonds.

[0151] The melting point of the crystalline polyol is preferably 35°C to 100°C. A melting point within this range improves the heat storage properties of the polyurethane. To improve this effect, the lower limit is more preferably 40°C, even more preferably 45°C, even more preferably 50°C, particularly preferably 55°C, and most preferably 60°C.

[0152] Examples of the repeating units in the main skeleton include 1,2-ethylene glycol unit, 1,2-propylene glycol unit, 1,3-propylene glycol (trimethylene glycol) unit, 2-methyl-1,3-propylene glycol unit, 2,2-dimethyl-1,3-propylene glycol unit, 1,4-butanediol (tetramethylene glycol) unit, 2-methyl-1,4-butanediol unit, 3-methyl-1,4-butanediol unit, 3-methyl-1,5-pentanediol unit, neopentyl glycol unit, 1,6-hexanediol unit, 1,7-heptanediol unit, 1,8-octanediol unit, 1,9-nonanediol unit, 1,10-decanediol unit, and 1,4-cyclohexanedimethanol unit.

[0153] Among these, from the perspective of improving the polyurethane's heat storage properties, heat resistance, and moldability (hereinafter sometimes referred to as "heat storage properties, etc."), it is preferred to include polyethylene glycol whose repeating units are 1,2-ethylene glycol units. In other words, the polyalkylene ether glycol preferably includes polyethylene glycol. From the perspective of further improving the aforementioned heat storage properties, etc., the polyethylene glycol content is preferably 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 100% by weight relative to the total amount of the polyalkylene ether glycol.

[0154] In addition, the number average molecular weight of the structural unit (B) is preferably in the range of more than 1000 and less than 10000. By making the number average molecular weight within the aforementioned range, the heat storage property and heat resistance of the polyurethane become good and the moldability is excellent. From the viewpoint of improving this effect, the lower limit is more preferably 1500, further preferably 2500, particularly preferably 2700, and especially preferably 3000. From the same viewpoint, the upper limit is more preferably 9000, further preferably 6000, and particularly preferably 4000. It should be noted that the number average molecular weight of the structural unit (B) derived from polyalkylene ether glycol can be obtained by the hydroxyl value obtained according to the acetic anhydride pyridine method.

[0155] From the viewpoint of efficiently absorbing heat from the battery, the number average molecular weight of the structural unit (B) is more preferably 1,500 or more and 10,000 or less, further preferably 2,000 or more and 10,000 or less, even more preferably 3,000 or more and 10,000 or less, particularly preferably 3,400 or more and 10,000 or less, and particularly preferably 4,000 or more and 10,000 or less.

[0156] Furthermore, in the polyurethane of the present invention, the weight fraction of the structural unit (B) relative to the total weight of the structural units (A) and (B) is preferably 50% by weight or more and 99% by weight or less. By setting the weight fraction of the structural unit (B) relative to the total weight of the structural units (A) and (B) within the aforementioned range, the melting enthalpy can be maximized. To improve this effect, the lower limit is preferably 60% by weight, more preferably 70% by weight, even more preferably 80% by weight, and even more preferably 90% by weight, and the upper limit is preferably 98% by weight.

[0157] In the aforementioned polyurethane, the ratio of the isocyanate group equivalent (II) of the structural unit (A) of the aromatic compound of the isocyanate group having an average functional group number of 2.1 or more to the hydroxyl equivalent (I) of the structural unit (B) derived from the crystalline polyol is preferably 0.4≤(II) / (I)≤1.2. By making the aromatic isocyanate / crystalline polyol ratio within the aforementioned range, a polyurethane having good heat storage and shape retention after melting can be formed. From the viewpoint of improving this effect, the lower limit is preferably 0.65, more preferably 0.70, and further preferably 0.80. From the same viewpoint, the upper limit is preferably 1.10, more preferably 1.05, and further preferably 1.00. It should be noted that the aromatic isocyanate / crystalline polyol ratio can be obtained by nuclear magnetic resonance (NMR) analysis.

[0158] The number average molecular weight of the structural unit (B) derived from polyalkylene ether glycol is preferably more than 1000 and less than 10000. By making the number average molecular weight within the aforementioned range, the heat storage property and heat resistance of the polyurethane become good and the moldability is excellent. From the viewpoint of improving this effect, the lower limit is preferably 2500, more preferably 2700, and further preferably 3000. From the same viewpoint, the upper limit is preferably 9000, more preferably 6000, and further preferably 4000. It should be noted that the number average molecular weight of the structural unit (B) derived from polyalkylene ether glycol is quantified by gel permeation chromatography of a solution containing a hydrolyzate of a polymer. "Waters Alliance 2695, 2414 (refractometer), 2996 (PDA)" manufactured by Waters Corporation, equipped with a gel permeation chromatograph connected to a photodiode array (PDA) detector, was used. A calibration curve of number average molecular weight and retention time was prepared using sodium polystyrene sulfonate with peak top molecular weights of 206, 4300, 6800, 17000, 32000, 77000, 15000, and 2600000 as standard samples. The retention time in the resulting chromatogram was converted to the number average molecular weight in terms of sodium polystyrene sulfonate.

[0159] [1-2. Specific physical properties of polyurethane]

[0160] The polyurethane according to one embodiment of the present invention exhibits a solid-solid phase transition. Generally, the solid-solid phase transition includes a phase transition accompanied by heat release and heat absorption. The phase transition temperature accompanied by heat release can be confirmed by the exothermic peak temperature in differential scanning calorimetry, and the phase transition temperature accompanied by heat absorption can be confirmed by the endothermic peak temperature in differential scanning calorimetry.

[0161] The exothermic peak temperature of the polyurethane of the present invention is preferably from 0°C to 80°C. The lower limit of the exothermic peak temperature is more preferably 20°C, more preferably 25°C, and even more preferably 30°C. The upper limit is more preferably 75°C, even more preferably 70°C, particularly preferably 65°C, especially preferably 60°C, and most preferably 50°C. By keeping the exothermic peak temperature within the aforementioned range, efficient heat and cold storage can be achieved.

[0162] From the viewpoint of efficiently absorbing heat in the battery, the exothermic peak temperature is preferably 0 to 80°C, more preferably 30 to 60°C.

[0163] From the viewpoint of controlling the exothermic peak temperature, the polyurethane is preferably a thermosetting polyurethane.

[0164] The exothermic peak temperature is determined using a differential scanning calorimeter. Specifically, it is carried out as follows. First, an aluminum pan containing about 5 mg of a sample is heated from room temperature at a heating rate of 1°C / min to a predetermined temperature by heating under a nitrogen atmosphere, and maintained at this temperature for 1 minute. Next, the pan is cooled to -10°C at a cooling rate of 1°C / min. The exothermic peak temperature can be determined from the DSC curve obtained during this cooling. Specifically, the maximum point of the exothermic curve in the range of 20°C to 80°C is determined, and the temperature at this maximum point is taken as the exothermic peak temperature.

[0165] The polyurethane's endothermic peak temperature is preferably 30°C to 90°C. The lower limit of the endothermic peak temperature is more preferably 35°C, further preferably 40°C, and particularly preferably 50°C. The upper limit is more preferably 85°C, further preferably 80°C, particularly preferably 75°C, and particularly preferably 70°C. By keeping the endothermic peak temperature within the aforementioned range, efficient heat and cold storage can be achieved.

[0166] From the viewpoint of efficiently absorbing heat in the battery, the endothermic peak temperature is preferably 30 to 90°C, more preferably 50 to 80°C.

[0167] From the viewpoint of controlling the endothermic peak temperature, the polyurethane is preferably a thermosetting polyurethane.

[0168] Furthermore, from the viewpoint of shape retention, it is preferable to include a temperature range where it is solid at or above the endothermic peak temperature, for example, preferably solid in the temperature range of 50 to 200° C. Here, solid means a gel fraction of 70% or more.

[0169] In other words, it is preferable that a phase transition accompanied by heat absorption is exhibited when the temperature is increased to the above-mentioned temperature.

[0170] Furthermore, polyurethane can be produced, for example, by adjusting the aromatic isocyanate / polyalkylene ether glycol ratio to within a predetermined range when producing polyurethane from a composition containing an aromatic polyisocyanate compound and a polyalkylene ether glycol as a raw material. The aromatic isocyanate / polyalkylene ether glycol ratio can be adjusted, for example, by adjusting the ratio of the aromatic polyisocyanate compound to the polyalkylene ether glycol.

[0171] The endothermic peak temperature is measured using a differential scanning calorimeter (DSC). Specifically, it is carried out as follows. First, by heating under a nitrogen atmosphere, an aluminum pan enclosing about 5 mg of a sample is heated at a heating rate of 1°C / min to a specified temperature and maintained for 1 minute. Next, it is cooled to -10°C at a cooling rate of 1°C / min and maintained for 1 minute. Thereafter, the temperature is again increased at a heating rate of 1°C / min to a specified temperature. The endothermic peak temperature can be determined from the DSC curve obtained in the second heating. Specifically, the minimum point of the endothermic curve in the range of 30°C to 90°C is obtained, and the temperature at the minimum point is taken as the endothermic peak temperature.

[0172] For polyurethane, the melting enthalpy observed by differential scanning calorimetry at 30°C to 90°C is preferably 50 J / g or higher, more preferably 70 J / g or higher, even more preferably 72 J / g or higher, and particularly preferably 74 J / g or higher. The upper limit of the melting enthalpy is not particularly limited, but is preferably 150 J / g or lower.

[0173] From the same viewpoint, the melting enthalpy per unit density observed at 30°C or higher and 90°C or lower by differential scanning calorimetry is preferably 50 J / cm 3 More than 70 J / cm 3 More preferably, 72 J / cm 3 Above, particularly preferably 74 J / cm 3 In addition, the upper limit of the melting enthalpy is not particularly limited, but is preferably 150 J / cm 3 the following.

[0174] The enthalpy of fusion refers to the heat of fusion at a portion within a temperature range of 30° C. to 90° C. in a melting curve measured by differential scanning calorimetry, and is obtained, for example, by the following method.

[0175] The measurement of the melting enthalpy is carried out in the same manner as the aforementioned endothermic peak temperature using a differential scanning calorimeter. The specific measurement is also carried out in the same manner as the endothermic peak temperature. Moreover, the DSC data (DSC curve) obtained in the second temperature increase is used as a measurement curve. The measurement point at 30°C and the measurement point at 90°C in the measurement curve are connected with a straight line. The total amount of the portion closer to the endothermic side relative to the straight line (the total amount is represented by the area of ​​the region enclosed by the straight line and the DSC curve) is used as the melting enthalpy. It should be noted that, when there is no peak in the measurement curve between 30°C and 90°C, the melting enthalpy is regarded as 0.

[0176] From the viewpoint of improving thermal conductivity, the density of polyurethane is preferably 1.0 to 10 g / cm 3 , more preferably 2 to 8 g / cm 3 .

[0177] From the viewpoint of increasing the density, the polyurethane is preferably a non-foamed polyurethane.

[0178] Furthermore, from the viewpoint of improving heat storage performance, the thermal conductivity of polyurethane is preferably 0.2 to 5.0 W / (m·K), and more preferably 1.0 to 3.0 W / (m·K).

[0179] When producing the polyurethane of the present invention, a catalyst may be used. The catalyst is not particularly limited as long as it can produce the polyurethane, and the following (C) catalysts can be preferably used.

[0180] [2. Composition]

[0181] The following describes a composition suitable for producing the polyurethane of the present invention (hereinafter also referred to as a potting material). The composition comprises an isocyanate (A) having an average functional group number of 2.1 or greater and a crystalline polyol (B). The composition may further comprise a catalyst (C).

[0182] Preferred embodiments of the isocyanate (A) and the crystalline polyol (B) having an average functional group number of 2.1 or more contained in the composition are the same as those described in [1. Polyurethane].

[0183] The composition may further contain an antioxidant, a filler, etc. which will be described later. Preferred embodiments of these agents are the same as those described in [4. Polyurethane composition for thermal storage material].

[0184] <Catalyst (C)>

[0185] The catalyst (C) used to produce the polyurethane of the present invention is preferably an organic catalyst, such as amines and imidazoles. When an aromatic polyisocyanate compound is used, the use of an organic catalyst can improve the activity of the urethanization reaction, thereby controlling the curing time and productivity during production.

[0186] As an organic catalyst, for example, an amine catalyst such as triethylenediamine, triethylamine, or N-ethylmorpholine, or an imidazole catalyst such as 1,2-dimethylimidazole, or a base catalyst (basic compound), or an acid catalyst such as acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, or sulfonic acid can be used. Of these, base catalysts are preferred, nitrogen-containing compounds are more preferred, and at least one of an amine catalyst and an imidazole catalyst is more preferred, preferably at least one of triethylenediamine and imidazole. The catalyst may be used alone or in combination of two or more.

[0187] From the viewpoint of controlling the curing time, it is preferred to contain two or more organic catalysts.

[0188] In addition, the amount of the catalyst added is preferably set to 10 ppm or more and 1000 ppm or less relative to 100 parts by weight of the total solid content in the composition for producing the polyurethane of the present invention (details will be described later). By making the amount of the catalyst added within the above range, polyurethane can be produced efficiently.

[0189] When a metal catalyst is used in combination, from the viewpoint of controlling the curing time, the metal content is preferably 20,000 ppm or less, preferably 10,000 ppm or less, more preferably 5,000 ppm or less, more preferably 1,000 ppm or less, more preferably 500 ppm or less, and more preferably 100 ppm or less, relative to 100 parts by weight of the total solid content or the composition.

[0190] From the viewpoint of maximizing enthalpy, in the composition of the present invention, the weight fraction of the crystalline polyol (B) relative to the total weight of the aromatic compound (A) having an isocyanate having an average functional group number of 2.1 or more, the crystalline polyol (B), and the catalyst (C) is preferably 50 to 99% by weight, more preferably 60 to 98% by weight.

[0191] In addition to the above-mentioned components (A), (B), and (C), the composition of the present invention may also contain a diol or a polyamine as a chain extender within a range that does not impair the physical properties.

[0192] Specific examples thereof include: straight-chain diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propanediol; Branched diols such as 1,3-propanediol, 2,4-heptanediol, 1,4-dimethylolhexane, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, and dimer diol; diols having ether groups such as diethylene glycol and propylene glycol; 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, Diols with alicyclic structures such as 1,4-dihydroxyethylcyclohexane; diols with aromatic groups such as xylene glycol, 1,4-dihydroxyethylbenzene, 4,4'-methylenebis(hydroxyethylbenzene); polyols such as glycerol, trimethylolpropane, pentaerythritol; hydroxyamines such as N-methylethanolamine, N-ethylethanolamine; ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine Polyamines such as 1,2-diamino-2,4-diamino-3-methyl-1-thiazolinone, 1,2-diamino-2-methyl-1-thiazolinone, 1,2-diamino-3 ...

[0193] These diols or polyamines may be used alone or in combination of two or more.

[0194] [3. Applications of polyurethane]

[0195] The polyurethane of the present invention is excellent in heat storage properties, heat resistance, moldability, shape retention, etc., and therefore is suitably used as a material for a heat storage material (heat storage material).

[0196] [4. Polyurethane composition for thermal storage material]

[0197] The polyurethane composition for heat storage materials of the present invention may also contain polyurethane for heat storage materials and other components. Here, as polyurethane for heat storage materials, the above-mentioned polyurethane can be suitably used. As other components, resins other than additives and polyurethane for heat storage materials (hereinafter, suitably referred to as "other resins") can be mentioned. Specifically, various additives can be added to polyurethane for heat storage materials within a range that does not impair the effect. As additives, phase change materials different from the above-mentioned polyurethane, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, fillers, neutralizers, lubricants, antifogging agents, anti-blocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity imparting agents, crosslinking agents, crosslinking aids, metal deactivators, molecular weight regulators, antibacterial agents, mildew-proof materials, fluorescent whitening agents, organic diffusers, inorganic diffusers and other light diffusers can be mentioned.

[0198] The antioxidant is not particularly limited as long as it does not hinder the effects of the present invention. Examples include phenolic antioxidants and phosphite antioxidants. Adding an antioxidant can reduce the rate of change in enthalpy before and after heat treatment. Specifically, the rate of change in enthalpy ΔH of the peak derived from polyurethane after treatment at 100°C for 200 hours is preferably 10% or less.

[0199] The content of the polyurethane for thermal storage materials in the polyurethane for thermal storage materials composition is preferably 80% or more and 99.9% or less. When the content of the polyurethane for thermal storage materials is within the above range, a high melting enthalpy can be obtained.

[0200] There are no particular limitations on fillers, provided they do not impair the effects of the present invention. Examples include silicon carbide, aluminum nitride, aluminum oxide, boron nitride, and silicon nitride. Adding fillers can improve thermal conductivity. Specifically, the filler content is preferably 0.1 to 60% by mass, more preferably 0.1 to 50% by mass, and even more preferably 0.1 to 40% by mass, relative to 100% by mass of the polyurethane composition for a thermal storage material.

[0201] In addition, other resins may be blended into the polyurethane for heat storage materials within a range that does not impair the effect. Specific examples of such other resins include polyethylene, polypropylene, polyester, polyester carbonate, aromatic polycarbonate, polyamide, polyimide, ABS, PMMA, and PET. For example, such other resins may be blended to improve shape retention.

[0202] [5. Method for producing polyurethane]

[0203] The following describes a method for producing polyurethane using, as polyurethane raw materials, a crystalline polyol, preferably a polyalkylene ether glycol, and an isocyanate compound having an average functional group number of 2.1 or more, preferably an aromatic polyisocyanate compound having an average functional group number of 2.1 or more.

[0204] For example, the polyurethane of the present invention can be obtained by mixing an isocyanate compound having an average functional group number of 2.1 or more, a crystalline polyol, and a catalyst.

[0205] The composition of the crystalline polyol and the isocyanate having an average functional group number of 2.1 or more can be set to a stoichiometric ratio such that the polyurethane satisfies a predetermined isocyanate group equivalent / polyol hydroxyl group ratio.

[0206] (Chain Terminator)

[0207] When producing polyurethane, a chain terminator having one active hydrogen group may be used as needed for the purpose of controlling the molecular weight of the obtained polyurethane.

[0208] Examples of the chain terminator include aliphatic monoalcohols having one hydroxyl group, such as methanol, ethanol, propanol, butanol, and hexanol; and aliphatic monoamines having one amino group, such as diethylamine, dibutylamine, n-butylamine, monoethanolamine, diethanolamine, and morpholine.

[0209] These may be used alone or in combination of two or more.

[0210] The upper limit of the amount of the chain terminator to be used is preferably 1000 ppm or less based on 100 parts by weight of the total amount of the polyurethane resin (structural units (A1) and (B1)).

[0211] (Polyols other than polyalkylene ether glycols)

[0212] In the polyurethane formation reaction when producing polyurethane, it is also possible to use, as needed, in combination with the polyalkylene ether glycol as the crystalline polyol (B) and a polyol other than the polyalkylene ether glycol. Here, the polyol other than the polyalkylene ether glycol is not particularly limited as long as it is a polyol commonly used in the production of polyurethanes. Examples thereof include polyester polyols, polycaprolactone polyols, and polycarbonate polyols. Here, the weight proportion of the polyalkylene ether glycol relative to the total weight of the polyalkylene ether glycol and the polyols other than the polyalkylene ether glycol is preferably 30% or more, more preferably 50% or more. If the weight proportion of the polyalkylene ether glycol is above the above lower limit, the heat storage properties of the polyurethane are improved.

[0213] (Equivalence ratio)

[0214] The amount of the aromatic polyisocyanate compound used is not particularly limited. However, based on the total number N1 of the hydroxyl groups of the polyalkylene ether glycol and the hydroxyl groups of the other polyols, the total number N2 of the hydroxyl groups of the chain extender, and the total number N3 of the amino groups (N1+N2+N3) as 1 equivalent, the amount is preferably 0.4 equivalents or more and 1.2 equivalents or less. A more preferred lower limit of the amount used is 0.65 equivalents, more preferably 0.70 equivalents, and even more preferably 0.80 equivalents. Based on the total as 1 equivalent, the upper limit of the amount used is preferably 1.10 equivalents, more preferably 1.07 equivalents, even more preferably 1.05 equivalents, and even more preferably 1.00 equivalents.

[0215] By adjusting the amount of the aromatic polyisocyanate compound used to below the aforementioned upper limit, side reactions of unreacted isocyanate groups can be suppressed, preventing changes in hardness over time. On the other hand, by adjusting the amount used to above the aforementioned lower limit, the molecular weight of the polyurethane is sufficiently high, making it less likely to melt even when heated, maintaining a gel fraction of 70% or higher, and improving shape retention.

[0216] The amount of chain extender used is not particularly limited. When the amount obtained by subtracting the total number of hydroxyl groups of the polyalkylene ether glycol and other polyols from the number of isocyanate groups of the aromatic polyisocyanate compound is taken as 1 equivalent, the lower limit of the amount used is preferably 0.7 equivalents, more preferably 0.8 equivalents, even more preferably 0.9 equivalents, and even more preferably 0.95 equivalents. The upper limit of the amount used is preferably 3.0 equivalents, more preferably 2.0 equivalents, even more preferably 1.5 equivalents, and even more preferably 1.1 equivalents. By setting the amount of chain extender used below the aforementioned upper limit, it is possible to prevent the polyurethane from becoming difficult to dissolve in solvents and becoming difficult to process. By setting the amount used above the aforementioned lower limit, it is possible to prevent the polyurethane from becoming excessively softened. This improves the strength, hardness, elastic recovery performance, and elasticity retention performance of the polyurethane, and also improves the heat resistance of the polyurethane.

[0217] Polyurethane is preferably a polyurethane elastomer. In this case, in the heat storage molded body described later, a heat storage molded body with excellent elasticity can be obtained. In addition, the shape retention based on heating and cold and hot of this heat storage molded body is also good.

[0218] Furthermore, the polyurethane elastomer is preferably a thermosetting type. Specifically, the polyurethane is preferably a thermosetting polyurethane elastomer. In this case, by forming a two-component curing type, filling molding (potting) becomes possible, and molding of complex shapes or large-volume products becomes possible.

[0219] [6. Method for producing polyurethane composition for thermal storage material]

[0220] The polyurethane composition for a thermal storage material can be produced, for example, by mechanically melt-kneading the aforementioned components of the composition. A single-screw extruder, a twin-screw extruder, or the like can be used as a melt-kneading machine. From the perspectives of productivity and quality uniformity, a method in which the components are continuously fed into the extruder to continuously produce the polyurethane composition is preferred.

[0221] [7. Thermal storage molded body]

[0222] The thermal storage molded article of the present invention is a molded article of the polyurethane or polyurethane composition for thermal storage material. As mentioned above, from the viewpoint of improving thermal conductivity, the density of the thermal storage molded article is preferably 1.0 to 10 g / cm 3 , more preferably 2 to 8 g / cm 3 .

[0223] From the viewpoint of improving heat storage performance, the thermal conductivity of the heat storage molded article is preferably 0.2 to 5.0 W / (m·K), more preferably 1.0 to 5.0 W / (m·K), and even more preferably 1.0 to 3.0 W / (m·K).

[0224] The thermal storage molded body is composed of a thermal storage material, for example, obtained by molding the thermal storage material. Specifically, the thermal storage material is molded into various shapes such as sheets, plates, granules, pellets, and tubes. The usual molding method is used for molding, specifically, extrusion molding, injection molding (specifically, insert molding, two-color molding, sandwich molding, gas injection molding, etc.) and the like. More specifically, the components mixed into a molten state during the manufacture of the thermal storage material can be directly (for example, at a temperature that maintains the molten state) or slightly cooled and then injected into a mold for molding. In addition, the thermal storage material will solidify at a temperature lower than its flow start temperature, so it can be cut after being molded into a block to form a sheet or plate. Furthermore, the thermal storage material can also be attached, coated or impregnated on a film, cloth, fiber, particleboard, etc. to form a sheet or plate. Alternatively, the thermal storage material can be packaged in a polyethylene bag or similar and formed into a sheet, plate, or rod during the cooling process. Alternatively, it can be extruded into a sheet or plate using an extruder. Rods or tubes formed using an extruder can also be cut into pellets or granules. There are no particular limitations on the apparatus or processing conditions for each molding method.

[0225] The shape of the thermal storage molded article is not particularly limited, and examples thereof include sheets, films, plates, granules, blocks, fibers, rods, porous bodies, and foams, with sheets, films, and plates being preferred. Furthermore, the article may be subjected to surface treatments commonly used in industry, such as corona discharge treatment, flame treatment, plasma treatment, and ozone treatment.

[0226] The thermal storage molded article preferably has an exothermic peak temperature (crystallization temperature) observed by differential scanning calorimetry of 20°C or higher and 80°C or lower. The lower limit of the exothermic peak temperature is more preferably 25°C, and even more preferably 30°C. The upper limit is more preferably 75°C, even more preferably 70°C, particularly preferably 65°C, and even more preferably 60°C. By setting the exothermic peak temperature within the above range, efficient thermal and cold storage can be achieved.

[0227] From the viewpoint of efficiently absorbing heat in the battery, the exothermic peak temperature is preferably 0 to 80°C, more preferably 30 to 60°C.

[0228] The exothermic peak temperature is determined using a differential scanning calorimeter. Specifically, it is carried out as follows. First, an aluminum pan containing about 5 mg of a sample is heated from room temperature at a heating rate of 1°C / min to a predetermined temperature by heating under a nitrogen atmosphere, and maintained at this temperature for 1 minute. Next, the pan is cooled to -10°C at a cooling rate of 1°C / min. The exothermic peak temperature can be determined from the DSC curve obtained during this cooling. Specifically, the maximum point of the exothermic curve in the range of 20°C to 80°C is determined, and the temperature at this maximum point is taken as the exothermic peak temperature.

[0229] The thermal storage molded article preferably has an endothermic peak temperature observed by differential scanning calorimetry (DSC) of 30°C or higher and 90°C or lower. The lower limit of the endothermic peak temperature is more preferably 35°C, further preferably 40°C, and particularly preferably 50°C. The upper limit is more preferably 85°C, further preferably 80°C, particularly preferably 75°C, and particularly preferably 70°C. When the endothermic peak temperature is within the above range, efficient heat and cold storage can be achieved.

[0230] From the viewpoint of efficiently absorbing heat in the battery, the endothermic peak temperature is preferably 30 to 90°C, more preferably 50 to 80°C.

[0231] The endothermic peak temperature is measured using a differential scanning calorimeter (DSC). Specifically, it is carried out as follows. First, by heating under a nitrogen atmosphere, an aluminum pan enclosing about 5 mg of a sample is heated from room temperature at a heating rate of 1°C / min to a specified temperature, and maintained for 1 minute. Next, it is cooled to -10°C at a cooling rate of 1°C / min and maintained for 1 minute. Thereafter, the temperature is again increased to a specified temperature at a heating rate of 1°C / min. The endothermic peak temperature can be determined from the DSC data (DSC curve) obtained in the second heating. Specifically, the minimum point of the endothermic curve in the range of 30°C to 90°C is obtained, and the temperature at the minimum point is taken as the endothermic peak temperature.

[0232] The thermal storage molded article preferably has a melting enthalpy of 70 J / g or greater, more preferably 72 J / g or greater, and even more preferably 74 J / g or greater, as measured by differential scanning calorimetry at a temperature of 30°C to 90°C. The upper limit of the melting enthalpy is not particularly limited, but is preferably 150 J / g or less.

[0233] The enthalpy of fusion refers to the heat of fusion at a portion within a temperature range of 30° C. to 90° C. in a melting curve measured by differential scanning calorimetry, and is obtained, for example, by the following method.

[0234] The measurement of the melting enthalpy is carried out in the same manner as the aforementioned endothermic peak temperature using a differential scanning calorimeter. The specific measurement is also carried out in the same manner as the endothermic peak temperature. Moreover, the DSC data (DSC curve) obtained in the second temperature increase is used as a measurement curve. The measurement point at 30°C and the measurement point at 90°C in the measurement curve are connected with a straight line. The total amount of the portion closer to the endothermic side relative to the straight line (the total amount is represented by the area of ​​the region enclosed by the straight line and the DSC curve) is used as the melting enthalpy. It should be noted that when there is no peak in the measurement curve between 30°C and 90°C, the melting enthalpy is regarded as 0.

[0235] (Extrusion molding)

[0236] When a molded body is obtained by extrusion molding, the molded body is manufactured, for example, as follows. First, each raw material is put into an extruder at a temperature at which the raw materials constituting the heat storage material are fully melted, and kneaded while melting. The molten kneaded material is discharged from a die head of various shapes, and then the discharge is cooled by air cooling or water cooling to obtain the desired molded body. As the extruder, any of a single-screw extruder and a twin-screw extruder can be used. From the viewpoint of dispersibility, a twin-screw extruder is preferably used.

[0237] (Injection Molding)

[0238] When producing a molded article by injection molding, the raw materials constituting the thermal storage material are fed into an extruder at a temperature at which they are sufficiently melted, and then injected into a mold of various shapes to produce the desired molded article. The molding temperature in this case is preferably within the same range as for extrusion molding.

[0239] <Applications of Thermal Storage Molded Articles>

[0240] The use of the thermal storage molded article is not particularly limited. Since the thermal storage performance, heat resistance, moldability, and shape retention are excellent, the thermal storage molded article is suitably used as a product or a member thereof that directly or indirectly requires heat or cold insulation performance.

[0241] Examples of products or components that directly or indirectly require heat preservation or cold insulation performance include building materials, furniture, interior decoration products, bedding, bathroom materials, vehicles, air-conditioning equipment, electrochemical products, thermal insulation containers, food packaging films, clothing, daily necessities, agricultural materials, fermentation systems, thermoelectric conversion systems, heat transfer media, electronic equipment, heat pumps, and lithium battery modules.

[0242] Among these, it can be suitably used as a building material, specifically, as a heat storage building material installed around pipes for underfloor heating (Japanese: underbed heating room) and central heating heat sources, or as a heat insulation application for planar heating appliances such as electric blankets.

[0243] Among these, the materials are particularly suitable for use in vehicles, lithium battery modules, and other battery materials, and are suitable for cooling battery packs described in detail below.

[0244] In the present invention, the heat source is not limited as long as it generates heat, and examples thereof include heat media such as water, oil, and gas, and electric heating wires.

[0245] In addition, the aforementioned heat storage molded body can maintain a solid state above the endothermic peak, so it can be molded into the shape of a building material. Once solidified, it will not return to a liquid state, so it can be used to be contained in a porous material, flow around a heat source, and solidify in an integrated molding.

[0246] Furthermore, the thermal storage molded body can be molded without a solvent, enabling direct injection into devices and components for solidification and integrated molding. Furthermore, the thermal storage material mitigates damage to devices and components caused by temperature fluctuations, thereby contributing to the extended life of these devices and components.

[0247] [7-1. Thermal storage building materials]

[0248] Thermal storage building materials include, for example, floor heating, central heating, heat pumps, electric furnaces, crude oil furnaces, and the like. The thermal storage building material of the present invention can be suitably used for these applications.

[0249] Furthermore, from the perspective of thermal insulation of buildings using thermal storage building materials, it is preferred that the polyurethane of the present invention be included. Furthermore, it is preferred that the thermal storage molded article comprise thermosetting polyurethane, that the thermal storage molded article have an exothermic peak temperature of 20 to 80°C, more preferably an endothermic peak temperature of 30 to 90°C, and preferably a melting enthalpy of 70 J / g or greater. The article preferably includes a temperature range where it remains solid above the endothermic peak temperature.

[0250] The thermal storage material is preferably solid at 50 to 200° C., more preferably solid at 50 to 180° C., and even more preferably solid at 50 to 160° C. By being solid within the above range, the thermal storage material does not liquefy.

[0251] In addition, one embodiment of the present invention is a thermal storage building material including a thermal storage material provided around a heat source. The surroundings in the present invention refer to a range affected by the heat source.

[0252] Another embodiment of the present invention is a thermal storage building material including a thermal storage material provided around a heat medium and a heat medium circulation pipe connected to the heat medium, or around an electric heating wire.

[0253] Furthermore, as another embodiment of the present invention, there is a mode in which the heat source is located under the floor or on the wall of a building.

[0254] From the viewpoint of efficiently insulating a building, it is preferable that the heat storage material disposed around a heat source is disposed in contact with the heat source.

[0255] One embodiment of the thermal storage building material including the thermal storage material provided around the heat source in the present invention is underfloor heating.

[0256] Specifically, in a building having a heat source and heat medium circulation pipes or electric heating lines under the floor, the heat storage building material includes a heat storage material around the heat source, heat medium circulation pipes or electric heating lines.

[0257] One embodiment of the thermal storage building material including the thermal storage material provided around the heat source in the present invention is central heating.

[0258] Specifically, the thermal storage building material has a thermal storage material around the thermal medium, thermal medium circulation pipes or heating wires in a building with multiple rooms, and is equipped to transfer heat to the entire building through thermal medium circulation pipes or heating wires.

[0259] [7-2. Surface heating appliances]

[0260] Planar heating appliances include electric blankets, electric heating pads, heaters, and electric heating clothing.

[0261] From the perspective of heat preservation of planar heating appliances, it is preferred that the aforementioned heat storage molded body contains thermosetting polyurethane, the exothermic peak temperature of the aforementioned heat storage molded body is 20 to 80°C, the preferably endothermic peak temperature is 30 to 90°C, and the more preferably melting enthalpy is 70 J / g or more, and it is preferably included in a temperature region where it is solid above the aforementioned endothermic peak temperature.

[0262] Furthermore, the planar heating device preferably includes the heat storage molded body containing polyurethane around the heating wire.

[0263] [7-3. Car seats]

[0264] The vehicle seat is installed in the vehicle to seat the vehicle's passengers.

[0265] From the perspective of heat preservation of vehicle seats, it is preferred that the thermal storage molded body comprises thermosetting polyurethane, and the thermal storage molded body preferably has an exothermic peak temperature of 20 to 80°C, preferably an endothermic peak temperature of 30 to 90°C, and more preferably a melting enthalpy of 70 J / g or greater. The thermal storage molded body preferably includes a temperature range where it remains solid above the endothermic peak temperature.

[0266] Furthermore, the vehicle seat preferably includes the heat storage molded body containing polyurethane around the heating wire.

[0267] [7-4. Battery Pack]

[0268] Battery packs are suitable for use in, for example, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric motorcycles, electric bicycles, electric-assisted bicycles, ships, aircraft, trains, uninterruptible power supplies (UPSs), home power storage systems, and power system stabilization battery systems that utilize renewable energy sources such as wind, solar, tidal, and geothermal energy. However, battery packs can also be used as power sources to supply power to devices other than these EVs.

[0269] One embodiment of the present disclosure is a battery pack including a plurality of unit cells and a heat storage molded body in contact with the unit cells.

[0270] From the viewpoint of cooling the unit cells, it is preferred that the thermal storage molded body comprises thermosetting polyurethane and that the thermal storage molded body has an endothermic peak temperature of 30 to 80°C.

[0271] From the viewpoint of efficiently cooling the unit cells, the thermal storage molded body preferably has a single endothermic peak temperature.

[0272] From the perspective of efficiently cooling the cells, the distance between any two cells is preferably 1.0 mm or greater, more preferably 1.5 mm or greater, more preferably 2.0 mm or greater, more preferably 2.5 mm or greater, more preferably 1.0 to 10 mm, and even more preferably 2.0 to 5.0 mm.

[0273] <Single Battery>

[0274] Figure 4 1 is a plan view showing an example of a single cell constituting a battery pack. Figure 5 for Figure 4 The front view of the single battery shown, Figure 6 This is a right side view of a single cell. Cell 200 is a rectangular parallelepiped with a height (H), width (W), and thickness (D). Terminals 210 and 220 are provided on its top surface. Cell 200 is, for example, a lithium-ion secondary battery comprising a positive electrode and a negative electrode capable of storing and releasing lithium ions, as well as an electrolyte. In addition to lithium-ion secondary batteries, other secondary batteries such as lithium-ion all-solid-state batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and lead-acid batteries can also be used.

[0275] Examples of the aforementioned single cells include prismatic, pouch-shaped, or cylindrical batteries. To achieve a cooling effect, the single cell and the thermal storage molded body may be in contact at least partially, or may be in contact through a packaging material covering the thermal storage molded body. Among these single cells, cylindrical batteries are preferred for ease of handling.

[0276] In addition, the shape of the thermal storage molded body can be appropriately designed according to the single cell.

[0277] <Battery Pack>

[0278] Figure 7 FIG. 1 shows a top view of a battery pack 100 formed by a plurality of cells 200 . Figure 8 To schematically illustrate the Figure 7 The battery pack 100 is shown in a side view with the side plate 300d removed. Figure 7 and Figure 8 In FIG, the battery pack 100 includes a housing 300 and a plurality of cells 200 housed in the housing 300. The housing 300 includes a bottom plate 300e and side plates 300a, 300b, 300c, and 300d standing along the outer periphery of the bottom plate 300e. Figure 7 and Figure 8 In the example, five cells 200 are shown, but the number of cells can be selected as appropriate. The positive terminals (e.g., terminal 210) and negative terminals (e.g., terminal 220) of adjacent (opposing) cells 200 across the thermal storage molded body 1 are electrically connected in series via busbar 301, so that the battery pack 100 outputs a predetermined amount of power.

[0279] <Battery Pack>

[0280] One embodiment of the present invention is a battery pack in which the battery pack is housed in a casing.

[0281] From the viewpoint of efficiently cooling the cells, the thermal storage molded body preferably has a continuous structure within the casing.

[0282] like Figure 8As shown, one embodiment of the battery pack 100 is as follows: a heat transfer plate 1A is disposed between the upper surface of the bottom plate 300 e of the housing 300 and each of the cells (prismatic cells) 200 .

[0283] From the perspective of efficiently cooling the cells, the battery pack preferably includes a heat transfer plate in contact with the cells and the heat storage molded body. More preferably, the heat transfer plate is disposed on the bottom of the heat storage material.

[0284] <Battery Pack Manufacturing Method>

[0285] One embodiment of the present invention is a method for manufacturing the aforementioned battery pack (hereinafter also referred to as a potting process). Figure 10 An example of a battery pack is shown.

[0286] The battery pack is manufactured by filling a battery assembly 700 , in which a plurality of single cells (cylindrical batteries) 400 are housed in a casing 500 , with a composition 600 serving as a potting material through a nozzle 800 .

[0287] The potting material is a composition 600 before heating (before curing reaction), and becomes polyurethane 610 after heating (after curing reaction). The polyurethane may be a polyurethane composition for thermal storage material that also contains an antioxidant and a filler, or a thermal storage molded body filled into a housing of a specific shape.

[0288] The method for manufacturing the battery pack preferably comprises filling a housing having a plurality of cells with a composition comprising an aromatic compound (A) having an average functional group number of 2.1 or greater, a crystalline polyol (B), and a catalyst (C). From the perspective of efficient filling, the method more preferably comprises at least one of the following steps: (1) heating the composition to a temperature above the melting point of the crystalline polyol; (2) heating the housing; and (3) heating the cells.

[0289] The steps (1) to (3) are preferably heated at a temperature above the melting point of the crystalline polyol, more preferably at 20 to 120°C, further preferably at 40 to 120°C, and particularly preferably at 60 to 120°C. Figure 10 As shown, the composition is filled using nozzle 800. From the perspective of efficient filling, it is preferred to fill the composition from at least two locations. It should be noted that at least two nozzles for filling the composition can be provided, or one nozzle can be moved to fill from multiple locations, or these can be combined.

[0290] Figure 11 A snapshot of the potting process.

[0291] The filling time is controlled by variables in the potting process, namely the distance between battery cells, the viscosity of the potting material, and the flow rate. By making the distance between battery cells small and the viscosity and flow rate of the potting material high, manufacturing efficiency is reduced.

[0292] In Experimental Example A, the relationship between the aforementioned variables and F, and the relationship with the gradient formed by the potting material were studied to study an efficient potting process.

[0293] Figure 12 and Figure 13 A cross-sectional view in the longitudinal direction of the battery pack is shown. Figure 13 The 870 in the figure represents a plane bisecting the battery pack in the short side direction. The cross-sectional view is a plane including three points: the foot 840 of a perpendicular line drawn from 830 to 810, the foot 850 of a perpendicular line drawn from 830 to 820, and the foot 860 of a perpendicular line drawn from 850 to 870. Figure 12 The cylindrical battery 900 closest to the nozzle has intersections with the potting material surface at both ends. The angle 910 of the gradient formed by the potting material is the angle formed by the line segment connecting the aforementioned intersections relative to the bottom surface of the battery pack.

[0294] The threshold angle 920 for the gradient is calculated from the shape of the battery pack as θ2 = arctan(X / Y). Here, X is the distance between the line segment 880, i.e., the foot 840 of a perpendicular line drawn from the nozzle tip 830 to the battery pack top surface 810, and the foot 850 of a perpendicular line drawn from the nozzle tip 830 to the battery pack bottom surface 820. X corresponds to the height of the cylindrical battery. Y is the distance between the line segment 890, i.e., the foot 850 of a perpendicular line drawn from the nozzle tip 830 to the battery pack bottom surface 820, and the foot 860 of a perpendicular line drawn from the foot 850 to a plane 870 that bisects the battery pack in the short direction. When the nozzle tip 830 is located on the bisecting plane 870, the threshold angle θ2 is calculated such that Y is 1 / 2 of the battery pack casing in the long direction. Furthermore, in the calculation of F shown in formula (II), the filling volume flow rate is set to 1 / 2 of the filling volume flow rate. If the gradient angle 910 is higher than the threshold angle 920 , it means that when the potting material is filled at a certain flow rate, the potting material overflows from the upper surface of the battery pack before reaching the point 860 .

[0295] Figure 14 The bottom of the battery pack is observed from a vertical direction Figure 12 A top view of the battery pack showing the top surface 810 of the battery pack. Figure 14 In the calculation of the gradient angle, Figure 13 When calculating the gradient angle 910, as shown in the left figure, the cross section passing through the center of the cylindrical battery 900 must be considered.

[0296] For example, if a cylindrical battery is asymmetrical in its casing, the cross-section may be underestimated by using the conventional method described above. Therefore, in this case, the cross-section is corrected by moving the vertical line 890 parallel to the short side so that it passes through the center of the cylindrical battery, as shown by the long double-dashed line.

[0297] From the viewpoint of improving cooling efficiency, the aforementioned composition is preferably filled with more than 50% relative to 100% of the height of the battery, more preferably more than 60%, more preferably more than 70%, more preferably more than 80%, and further preferably less than 100%, preferably less than 97%, more preferably less than 95%, more preferably less than 90%, more preferably less than 85%.

[0298] From the viewpoint of efficient filling, it is preferred to use the viscosity (Pa·s) of the composition at the time of filling, the filling volume flow rate (m 3 / s), and the minimum value (m) of the distance between batteries arranged in the case, is adjusted so that F in the formula (I) becomes 1.5N or less.

[0299] F = (viscosity of the composition) 0.53 ×(filling volume flow rate) 0.62 / (Minimum distance between multiple batteries placed in the housing) 1.3 ···(I)

[0300] Here, F refers to the resistance to the flow of the potting material between the cylindrical cells when the potting material is filled. A larger F value, i.e., a greater resistance to the flow of the potting material, makes it less likely for the potting material to flow within the battery pack, and increases the angle 910 formed by the gradient of the potting material.

[0301] From the perspective of efficient filling, F is preferably adjusted so that the angle θ1 of the gradient formed by the potting material during filling, calculated by the following formula (II) and the following formula (III), is 40° or less. The angle θ1 is preferably 35° or less, more preferably 30° or less, further preferably 25° or less, even more preferably 20° or less, particularly preferably 15° or less, and most preferably 12° or less.

[0302] (When 0°≤θ<3°)

[0303] F = 1.31 × 10 -1 ×(the angle of the gradient formed by the potting material relative to the bottom surface of the battery pack during filling: θ1)-1.44×10 -2 Formula (II)

[0304] (When θ≥3°)

[0305] F = 3.93 × 10 -2 ×(the angle of the gradient formed by the potting material relative to the bottom surface of the battery pack during filling: θ1)-5.02×10 -2 Formula (III)

[0306] When adjusting the aforementioned F, it is preferred to use a polyol having a viscosity of 1.0 Pa·s or less at 25°C, more preferably a polyol having a viscosity of 0.8 Pa·s or less at 25°C, further preferably a polyol having a viscosity of 0.6 Pa·s or less at 25°C, further preferably a polyol having a viscosity of 0.4 Pa·s or less at 25°C, and particularly preferably a polyol having a viscosity of 0.2 Pa·s or less at 25°C.

[0307] When adjusting the above-mentioned F, it is preferable to reduce the filling volume flow rate of the composition to 2.0×10 -7 m 3 / s, more preferably reduced to 1.0×10 -7 m 3 / s, and further preferably reduced to 0.5×10 -7 m 3 / s, particularly preferably reduced to 0.2×10 -7 m 3 / s.

[0308] When adjusting F, the distance between the cells is preferably 1.0 to 4.0 mm, more preferably 1.0 to 3.0 mm, and even more preferably 1.0 to 2.0 mm.

[0309] From the perspective of efficiently cooling the single cells, the method for using the battery pack preferably includes the following steps: a step of heating the battery pack to an endothermic temperature; and a step of cooling the battery pack at a rate of 100°C / minute or less, more preferably 75°C / minute or less, further preferably 50°C / minute or less, further preferably 25°C / minute or less, particularly preferably 10°C / minute or less, even more preferably 5°C / minute or less, and particularly preferably 1°C / minute or less.

[0310] It is preferred to include the step of maintaining the temperature above the endothermic temperature for 1 minute or longer.

[0311] <How to use the battery pack>

[0312] One embodiment of the present invention is a method for using the aforementioned battery pack.

[0313] The aforementioned method preferably includes the steps of: raising the temperature to a temperature equal to or higher than the endothermic peak temperature; and cooling the temperature to a temperature equal to or lower than the exothermic peak temperature.

[0314] The method preferably includes the steps of: charging a battery in contact with the heat storage molded body at C / 3 or higher; and absorbing heat generated by the battery by utilizing a phase change of the polyurethane.

[0315] In the above method, after the curing reaction, the heat storage molded article is further heated for a predetermined time at a temperature above the endothermic peak temperature. The lower limit of the predetermined time is preferably 1 minute or more, more preferably 5 minutes or more, more preferably 10 minutes or more, more preferably 30 minutes or more, more preferably 1 hour, and more preferably 2 hours or more. The upper limit of the predetermined time is preferably 1 hour.

[0316] Example

[0317] The invention is further described in detail below with reference to Examples and Comparative Examples. However, the invention is not limited to these Examples unless the scope of the invention is exceeded. It should be noted that the Examples describe an example using a polyurethane elastomer for a thermal storage material as the polyurethane for a thermal storage material.

[0318] [Evaluation Method]

[0319] The evaluation methods of the polyurethane elastomer for thermal storage materials, thermal storage materials and thermal storage molded articles containing the same obtained in the following Examples and Comparative Examples are as follows.

[0320] [Evaluation of Thermal Storage Molded Article]

[0321] <Endothermic Peak Temperature>

[0322] By heating under a nitrogen atmosphere, an aluminum pan containing about 5 mg of a sample was heated from 25°C to 80°C at a heating rate of 1°C / min and held for 1 minute. Next, the temperature was cooled to -10°C at a cooling rate of 1°C / min and held for 1 minute. After that, the temperature was again raised to 80°C at a heating rate of 1°C / min. The endothermic peak temperature was determined from the DSC data (DSC curve) obtained in the second heating. Specifically, the minimum point of the endothermic curve in the range of 30°C to 60°C was obtained, and the temperature at the minimum point was taken as the endothermic peak temperature.

[0323] <Melting Enthalpy>

[0324] According to the same method as the measurement of the aforementioned endothermic peak temperature, DSC data (DSC curve) is obtained. The DSC data is used as a measurement curve. The measurement point at 30°C and the measurement point at 60°C of the measurement curve are connected with a straight line. The total amount of the portion closer to the endothermic side relative to the straight line is used as the melting enthalpy. It should be noted that the total amount is represented by the area of ​​the region enclosed by the straight line and the DSC curve. In addition, when there is no peak in the measurement curve between 30°C and 60°C, the melting enthalpy is regarded as 0.

[0325] <Exothermic Peak Temperature>

[0326] Under a nitrogen atmosphere, an aluminum pan containing approximately 5 mg of a sample was heated from 25°C to 80°C at a rate of 1°C / minute and held for 1 minute. The sample was then cooled to -10°C at a rate of 1°C / minute and held for 1 minute. The exothermic peak temperature was determined from the DSC curve obtained during this cooling process. Specifically, the maximum point of the exothermic curve within the range of 30°C to 60°C was determined, and the temperature at this maximum point was defined as the exothermic peak temperature.

[0327] <Phase state at 80°C>

[0328] If the thermal storage material is held at a temperature higher than its endothermic peak temperature and liquefies, it may leak out and lose its thermal storage function. Therefore, the phase state after melting is evaluated. The following material, cut into 30 x 30 mm pieces, is used as a test sample. Place it on an 80°C hot plate and cover it with a glass petri dish. After 15 minutes, use a spatula to check for fluidity when touching the test sample to determine the phase state.

[0329] The case of solid was evaluated as ◯, and the case of liquid was evaluated as ×.

[0330] Example 1

[0331] <Manufacturing of Polyurethane Elastomer for Thermal Storage Materials>

[0332] 170.0 g of commercially available polyalkylene ether glycol ("PEG4000S" manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 33 mgKOH / g (number average molecular weight 3400)) heated to 65° C. was weighed into a disposable cup.

[0333] 0.26 g of a catalyst solution was added separately and stirred and mixed thoroughly with a three-in-one motor. The catalyst solution was prepared by dissolving triethylenediamine manufactured by Tokyo Chemical Industry Co., Ltd. as a urethane catalyst and polypropylene glycol manufactured by Sanyo Chemical Industry Co., Ltd., namely SANNIX PP-2000, in a ratio of 1:9, at 80°C and returning to room temperature.

[0334] To this was added 8.2 g of Millionate MR-200 (NCO content 30.8%), an aromatic compound having a polyfunctional (average number of functional groups: 2.8) isocyanate group and manufactured by Tosoh Corporation (hereinafter referred to as "p-MDI"). The mixture was stirred and mixed at 300 rpm for 5 minutes to allow the reaction to proceed.

[0335] The isocyanate weight was calculated according to Formula 1, with the NCO Index, which is the ratio of the isocyanate equivalent to the hydroxyl equivalent, being set to 0.6.

[0336] [Mathematical formula 1]

[0337]

[0338] A silicone release film was then placed on a glass plate, and a silicone mold (15 cm x 15 cm, 2 mm thick) was placed on top. The resulting mixture was poured into the mold, and then covered with the release film and then the glass plate. A weight was then placed on the glass plate above the mold, and the mixture was cured for another 30 minutes. The next day, the mixture was removed from the silicone mold to obtain a polyurethane elastomer for thermal storage materials (15 cm x 15 cm, 2 mm thick). After aging at room temperature for one week, the resulting product was used for evaluation.

[0339] The DSC curve of the polyurethane elastomer produced in Example 1 at the time of temperature increase is shown in FIG. Figure 1 In addition, the DSC curve during cooling is shown in Figure 2 The endothermic peak temperature was 56°C and the exothermic peak temperature was 41°C.

[0340] In addition, Table 1 shows the evaluation results.

[0341] [Examples 2 to 5]

[0342] A polyurethane elastomer for a thermal storage material was obtained in the same manner as in Example 1 except that the amounts described in Table 1 were changed. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[0343] [Comparative Example 1]

[0344] A polyurethane elastomer for a thermal storage material was obtained in the same manner as in Example 1 except that the bifunctional diisocyanate was changed to 4,4'-diphenylmethane diisocyanate (hereinafter referred to as "MDI") manufactured by Tosoh Corporation, namely Millionate MT, and melted at 70°C for use.

[0345] Table 1 shows the evaluation results of the physical properties of the thermal storage molded article.

[0346] [Examples 6 to 8]

[0347] In Example 1, a polyurethane elastomer for a thermal storage material was obtained in the same manner as in Example 1, except that the polyols listed in Table 1 were used, the amount of isocyanate added was adjusted to the amount listed in Table 1, and no catalyst was used. The results of the evaluations performed in the same manner as in Example 1 are shown in Table 1.

[0348] It should be noted that the PEG ratio in Table 1 refers to the weight fraction of the structural unit (B) relative to the total weight of the structural units (A) and (B).

[0349] [Table 1]

[0350] Table 1

[0351]

[0352] As is clear from Table 1, the polyurethanes for thermal storage materials of Examples 1 to 8, which contain specific structural units, and the thermal storage molded articles thereof, exhibit excellent thermal storage properties and shape retention. In contrast, the phase state of Comparative Example 1, which does not contain specific structural units, is liquid at 80°C, and its shape retention is insufficient.

[0353] In addition, Examples 6 to 8 are polyurethanes for heat storage materials and heat storage molded articles thereof having different molecular weights of polyols, but are excellent in heat storage properties and shape retention properties as in Examples 1 to 5.

[0354] [Examples 9 to 14]

[0355] In Example 2, a polyurethane elastomer for a thermal storage material was obtained in the same manner as in Example 2 except that the antioxidant described in Table 2 was added in the amount described in Table 2. The results of the evaluations performed in the same manner as in Example 2 are shown in Table 2.

[0356] In addition, the antioxidant used here is as follows.

[0357] AO-30: ADK STAB AO-30 (phenolic antioxidant, manufactured by ADEKA Co., Ltd.)

[0358] AO-40: ADK STAB AO-40 (phenolic antioxidant, manufactured by ADEKA Co., Ltd.)

[0359] [Table 2]

[0360] Table 2

[0361]

[0362] As can be seen from Table 2, the addition of the antioxidant minimizes the enthalpy change rate.

[0363] [Evaluation of thermal storage building materials including thermal storage molded bodies]

[0364] [Example 15]

[0365] A simulation on the temperature change suppression effect was performed under the following conditions.

[0366] <Molding>

[0367] The phase change material (PCM) of Example 2 was used as a potting material filled around the exothermic body. After the phase change material finished absorbing heat, the heating by the exothermic body was stopped, and the temperature drop caused by the external air temperature was calculated by simulation.

[0368] Thermal storage building materials

[0369] A simulation was performed on a building having underfloor heating using the thermal storage material of Example 2 as a thermal storage building material.

[0370] The building dimensions are as follows: the outer skin area is 300m 2 (Floor 10m x 10m, height 2.5m), and the UA value, an indicator of wall insulation performance, was set to 0.38W / mK. The underfloor heating system consists of a heat dissipator (hot water supply capacity 100L), a heat storage molded body, and flooring material. However, for simplicity, the simulation treated them as a single component, and the calculations were performed assuming anisotropic thermal conductivity.

[0371] The thermal storage molded body was set to 800 kg (9.0 m×9.0 m, thickness 8.23 ​​mm).

[0372] The room is configured using Figure 3 A cubic single-room model like that.

[0373] As initial temperatures, the outside air temperature was set to 0°C, the heat storage molded body was set to 42°C, the heat release body was set to 42°C, and the room temperature was set to 25°C.

[0374] The outside air temperature was fixed at 0°C, and after stopping the heating by the heat dissipation element, the temperature changes of the floor (including the heat storage molded body and the heat dissipation element) and the room were simulated. (Thermal insulation performance UA value = 0.38W / mK)

[0375] The physical properties of each component used in the calculation are as shown in Table 3.

[0376] [Table 3]

[0377] Table 3

[0378] Thermal storage molded body Specific heat J / kg·K 2000 density <![CDATA[kg / m 3 ]]> 1200 Thermal conductivity W / m·K 0.3

[0379] [Example 16]

[0380] The calculation conditions were set in the same manner as in Example 15, and simulation was performed except that the amount of the thermal storage molded body was changed to 300 kg (thickness 3.09 mm).

[0381] [Example 17]

[0382] The simulation was carried out by setting the calculation conditions in the same manner as in Example 15 except that the DSC data of the heat storage molded article were shifted by -15°C.

[0383] [Example 18]

[0384] The calculation conditions were set in the same manner as in Example 15, and simulation was performed except that the DSC data of the thermal storage molded article was shifted by -10°C.

[0385] [Example 19]

[0386] The simulation was performed by setting calculation conditions in the same manner as in Example 15 except that the shape of the thermal storage molded article was changed to (8.0 m×8.0 m, thickness 10.42 mm).

[0387] [Comparative Example 2]

[0388] The calculation conditions were set and simulation was performed in the same manner as in Example 15 except that the melting enthalpy of the thermal storage molded article was set to 0 J / g.

[0389] [Comparative Example 3]

[0390] The calculation conditions were set and simulation was performed in the same manner as in Example 16 except that the melting enthalpy of the thermal storage molded article was 60 J / g, the endothermic peak was 32° C., and the exothermic peak was 28° C.

[0391] [Comparative Example 4]

[0392] The calculation conditions were set and simulation was performed in the same manner as in Example 15 except that the melting enthalpy of the heat storage molded body was set to 0 J / g and the hot water supply amount was set to 370 L.

[0393] The simulation results were obtained for the average temperature in the building after 3 hours and 6 hours in Examples 15 to 19 and Comparative Examples 2 to 4. The results are shown in Table 4.

[0394] [Table 4]

[0395] Table 4

[0396] - Comparative Example 2 Example 15 Example 16 Example 17 Example 18 Example 19 Comparative Example 3 Comparative Example 4 Exothermic peak temperature [℃] - 40 40 25 30 40 28 - Endothermic peak temperature [℃] - 54 54 39 44 54 32 - Melting enthalpy (J / g) - 90 90 90 90 90 60 - Total enthalpy (kJ) - 72000 27000 72000 72000 72000 48000 - Average room temperature after 3 hours [℃] 6.4 24.7 22.8 17.9 18.8 22.4 17.3 16.2 Average room temperature after 6 hours [℃] 1.3 24.7 10.6 15.4 18.5 22.4 10.3 9.4

[0397] [Evaluation of spacers containing thermal storage molded articles]

[0398] [Experimental Example A]

[0399] A simulation on the temperature rise suppression effect was performed under the following conditions.

[0400] <Molding>

[0401] The temperature rise during 2C charging was calculated using a simulation using a phase change material with a melting enthalpy that begins to appear at 40°C and peaks at 53°C as the potting material surrounding a cylindrical battery cell. Numerical fluid dynamics software (product name: STAR-CCM+, Siemens) was used for the simulation.

[0402] <Battery Units and Charging Conditions>

[0403] The battery cell dimensions are as follows: 21mm in diameter and 70mm in height, including the 0.3mm thickness of the shell. The contents of the battery cell consist of a positive electrode, a negative electrode, a separator, an electrolyte, etc. However, in the simulation, for simplicity, they were treated as one component and the thermal conductivity was anisotropic for calculation. Figure 9 Such a 1 / 6 cake cut model. Figure 9 In the figure, the circles represent battery cells, and the model shows that the space between the battery cells is filled with phase change material.

[0404] The heat generated in each battery cell during 2C charging is set to a constant 4.4W for 30 minutes, and the initial temperature of each component constituting the assembly is set to 35°C. It should be noted that this condition assumes that charging will be performed immediately after the operation is completed. It is assumed that the bottom surface of the battery cell and the bottom of the phase change material (PCM) are in contact with the cooling mechanism, the refrigerant temperature is set to 30°C, and the heat transfer coefficient is set to 800W / m 2 Forced convection boundary conditions for K. Assuming the upper surface is a space, the air temperature is 30°C, and the heat transfer coefficient is 10 W / m 2 K natural convection boundary. The cutting surface is set as the symmetric boundary. In addition, it is assumed that an insulating sheet is provided at the bottom surface of the housing and the contact part of the battery cell, and the thermal resistance is set to 1.0×10 -4 m 2 K / W. The "maximum temperature difference of the battery cell during charging" was calculated by comparing it with the case where no phase change material was used. The physical properties used in the various components for this calculation are shown in Table 5.

[0405] [Table 5]

[0406] Table 5

[0407]

[0408] The simulation results are shown in Table 6.

[0409] [Table 6]

[0410] Table 6

[0411] Experimental Example A1 Experimental Example A2 Experimental Example A3 Experimental Example A4 Endothermic peak temperature [℃] 53 53 53 53 Endothermic start temperature [℃] 40 40 40 40 Thermal conductivity [W / m·K] 0.3 0.3 0.3 0.3 Distance between battery cells [mm] 0.5 1 2 6 Total heat absorption [kJ / kg] 96 96 96 96 Maximum temperature difference of the maximum temperature of the battery cell during charging [°C] 1.4 2.8 3.1 2.8

[0412] The results of Experimental Examples A1 to A4 show the effect of suppressing the temperature increase of a battery cell during charging by the molded article of the present invention.

[0413] [Example B]

[0414] A simulation on the temperature rise suppression effect was performed under the following conditions.

[0415] <Molding>

[0416] Same as Experimental Example A.

[0417] <Battery Units and Charging Conditions>

[0418] The same model as in Experimental Example A was used. The charging conditions were the same as in Experimental Example A, except that the upper surface of the battery cell was assumed to be a space and the air temperature was set to 35°C. The physical properties used in the calculations for each component are shown in Table 6. Note that the thermal conductivity of the phase change material molded body containing filler was 2.0 W / m·K, 4.0 W / m·K, and 6.0 W / m·K. Charging simulations were performed using these values, and the average of the calculated results for each thermal conductivity was used to calculate Indices 1 and 2.

[0419] [Table 7]

[0420] Table 7

[0421]

[0422] The simulation was conducted using the filler content (vol%) and the latent heat value (kJ / kg) of the phase change material molded article as variables. As the filler content in the phase change material molded article increases, the proportion of the phase change material in the molded article decreases, and the latent heat value of the phase change material molded article decreases. As the latent heat value of the phase change material increases, the latent heat value of the phase change material molded article also increases.

[0423] <Definition of evaluation indicators>

[0424] The difference between the cumulative value of the time when the average cell temperature exceeded 41°C from the start of 2C charging to 10 minutes and the comparative example was defined as Index 1. A smaller Index 1 means a shorter time at the initial stage of charging when the battery cell is at a temperature that accelerates cell degradation.

[0425] The difference between the average battery cell temperature after the completion of 2C charging and that of the comparative example is defined as Index 2. A lower Index 2 means that the battery cell is not in a high temperature state that accelerates degradation at the completion of charging.

[0426] <Evaluation Criteria>

[0427] The effect of suppressing the temperature rise during charging was evaluated using indexes 1 and 2.

[0428] If the indicator 1 is less than -200 seconds, it is scored as 3 points; if it is less than -150 seconds and -200 seconds or more, it is scored as 2 points; if it is less than -100 seconds and -150 seconds or more, it is scored as 1 point.

[0429] If the index 2 is less than -1.5°C, it is scored as 1 point.

[0430] The effect of suppressing the temperature rise during charging was evaluated using the total score of the scores of indicator 1 and indicator 2 as the evaluation value. A higher evaluation value means a greater effect of suppressing the temperature rise during charging.

[0431] <Evaluation Results>

[0432] [Table 8]

[0433] Table 8

[0434]

[0435] <Inspection>

[0436] In all of Examples B1 to B3, the evaluation values ​​were all 2 or greater, indicating that the addition of a filler to the phase-change material molded body has the effect of suppressing the temperature rise during charging.

[0437] When the latent heat amount of the phase change material is 100 kJ / kg, the evaluation value is 4, and the effect of suppressing the temperature rise during charging is particularly high.

[0438] As the filler content in the phase change material molded body increases, the thermal conductivity of the phase change material molded body increases, which has the effect of promoting heat release from the battery cell to the cooling surface. On the other hand, as the proportion of the phase change material in the phase change material molded body decreases, the heat absorption of the phase change material molded body decreases.

[0439] The results of Examples B1 to B3 show that in the trade-off between promoting heat release of the battery cell to the cooling surface and reducing the amount of heat absorbed by the phase change material molded body, adding filler to the phase change material molded body has the effect of suppressing the temperature rise during charging.

[0440] [Experimental Example C]

[0441] A simulation of the potting process was performed under the following conditions.

[0442] <Molding>

[0443] Assuming the potting material (composition) to be a fluid with a certain viscosity, the three-dimensional flow simulation is used to calculate the behavior of the fluid as it flows between the cylindrical batteries and gradually fills the pack. The density of the fluid is set to 998 kg / m3 .

[0444] <Battery cells and flow conditions>

[0445] The battery cell dimensions were set to 46 mm in diameter and 80 mm in height. A battery cell consists of a housing, positive electrode, negative electrode, separator, and electrolyte, but for simplicity, the simulation was performed as a single component.

[0446] In the calculation, a configuration with 4 Figure 12 A model of a cylindrical battery like the 400. Figure 12 In the diagram 400, the cylinder represents the battery cell, and the small circular area represents the resin inlet. The sidewall and bottom surfaces closest to the fluid inlet are treated as wall surfaces, and the remaining three sidewall surfaces are treated as symmetrical boundaries. The top surface serves as the boundary for air outflow from the package and is shown in an open state.

[0447] The fluid flows in from the inlet at a certain flow rate. The calculation ends when the upper surface of the fluid reaches the height of the battery cell at a certain point. Figure 14 The angle of the gradient mentioned in θ1.

[0448] The filling volume flow rate (m 3 The above simulation was performed using the viscosity (Pa·s) of the fluid (composition), and the minimum value (m) of the distance between batteries arranged in the case as variables.

[0449] <Indicator Definition>

[0450] By the viscosity of the fluid (Pa·s), filling volume flow rate (m 3 F is defined by the formula (1) defined by the minimum value (m) of the distance between batteries arranged in the casing.

[0451] F = (viscosity of the fluid) 0.53 ×(filling volume flow rate) 0.62 / (Minimum distance between multiple batteries placed in the housing) 1.3 ···(1)

[0452] When the potting material reaches the upper surface of the battery pack, the composition cannot be filled at a flow rate exceeding a certain level, and the total filling time becomes longer. The simulation results are shown in Table 9.

[0453] [Table 9]

[0454] Table 9

[0455]

[0456] Furthermore, the threshold value θ2 for the gradient angle θ1 is calculated based on the shape of the battery pack. Specifically, the threshold value θ2 for the gradient angle θ1 is defined by the following equation (2), depending on the distance 880 between 840 and 850 and the distance 890 between 850 and 860. Table 10 shows an example of the relationship between θ1 calculated by equation (2) and the length of the long side of the housing.

[0457] (Angle of gradient: θ2) = arctan (distance between 840 and 850) / (distance between 850 and 860) × 180° / π (2)

[0458] The results of Experiments C1 to C28 shown in Table 9 indicate that the relationship between F and the gradient angle θ1 is expressed as Equations (3) and (4). By considering the relationships between Equations (2), (3), and (4), the value of F is adjusted to reduce the gradient angle θ1, thereby achieving a filling condition that allows the housing to be filled in a shorter time.

[0459] (When 0°≤θ1<3°)

[0460] F = 1.31 × 10 -1 ×(the angle of the gradient formed by the potting material relative to the bottom surface of the battery pack during filling: θ1)-1.44×10 -2 ···(3)

[0461] (When 3°≤θ1)

[0462] F = 3.93 × 10 -2 ×(the angle of the gradient formed by the potting material relative to the bottom surface of the battery pack during filling: θ1)-5.02×10 -2 ···(4)

[0463] [Table 10]

[0464] Table 10

[0465]

[0466] Industrial applicability

[0467] According to the present invention, there can be provided a polyurethane for a thermal storage material having excellent thermal storage properties and heat resistance, excellent moldability, and good shape retention properties under heating and cooling, even without containing an additive having a thermal storage function, and a thermal storage material and a thermal storage molded article containing the same.

[0468] The present invention is particularly useful as a thermal storage building material and the like and has high industrial value.

[0469] Description of Reference Numerals

[0470] 10 Flooring

[0471] 20 Thermal storage molding

[0472] 30 heat release body (hot water pipe)

[0473] 1 partition member

[0474] 100 battery pack

[0475] 110 packaging material

[0476] 120 exterior materials

[0477] 200 single batteries

[0478] 210 terminal

[0479] 220 terminal

[0480] 300 shell

[0481] 300a side panels

[0482] 300b side panels

[0483] 300c side panels

[0484] 300d side panels

[0485] 300e baseplate

[0486] 301 busbar

[0487] 1A thermal conductive plate

[0488] 400 cylindrical battery (single cell)

[0489] 500 shell

[0490] 600 composition (before curing)

[0491] 610 polyurethane, polyurethane composition for thermal storage material, thermal storage molded body (after curing)

[0492] 700 battery pack

[0493] 800 nozzles

[0494] Top surface of the 810 battery pack

[0495] The bottom of the 820 battery pack

[0496] 830 nozzle front end point

[0497] 840 is the foot of the perpendicular line drawn from 830 to 810

[0498] 850 is the foot of the perpendicular line drawn from 830 to 820

[0499] 860 is the foot of the perpendicular line drawn from 840 to 870

[0500] The bisection of the 870 battery pack

[0501] 880 Distance between 840-850

[0502] 890 Distance between 850-860

[0503] 900 is the cylindrical battery closest to 830 in the long side direction

[0504] 910 gradient angle

[0505] 920° angle threshold

Claims

1. A polyurethane, characterized in that The polyurethane comprises a structural unit (A) derived from an aromatic compound having an isocyanate group with an average functional group number of 2.1 or more and a structural unit (B) derived from a polyalkylene ether glycol, wherein the polyurethane has an exothermic peak temperature of 0 to 50°C.

2. The polyurethane according to claim 1, wherein The structural unit (B) has a linear structure and does not have an unsaturated bond.

3. The polyurethane according to claim 1, wherein The weight fraction of the structural unit (B) relative to the total weight of the structural units (A) and (B) is 50% by weight or more and 99% by weight or less.

4. The polyurethane according to claim 1, wherein The number average molecular weight of the structural unit (B) is within the range of 1,000 or more and 10,000 or less. The polyurethane according to claim 1 , which shows a phase transition accompanied by endothermicity when heated to 30 to 90° C.

6. The polyurethane according to claim 1, wherein The polyurethane shows a phase transition accompanied by endothermic reaction when heated at 30 to 90° C., and the melting enthalpy in the phase transition is 50 J / g or more.

7. The polyurethane according to claim 1, wherein The structural unit (A) comprises a polymethylene polyphenyl polyisocyanate structural unit.

8. The polyurethane according to claim 1, wherein The ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B) is 0.4≤(II) / (I)≤1.

2.

9. The polyurethane according to claim 1, having a density of 1.0 to 10 g / cm 3 .

10. The polyurethane according to claim 1, wherein the thermal conductivity is 0.2 to 5.0 W / (m·K).

11. The polyurethane according to claim 1, further comprising an antioxidant.

12. A method for producing polyurethane, comprising mixing an aromatic compound having an isocyanate group having an average functional group number of 2.1 or more, a polyalkylene ether glycol, and a catalyst to obtain the polyurethane. 13 . A heat storage material comprising the polyurethane according to claim 1 . 14 . A battery pack comprising: a plurality of unit cells; and the polyurethane according to claim 1 in contact with the unit cells.

15. A building material comprising the polyurethane according to any one of claims 1 to 11.

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