Composite heat insulation pad, battery and electric device

Abstract

The invention relates to a composite heat insulation pad, a battery and an electric device. The composite heat insulation pad comprises a composite phase change layer, the composite phase change layer comprises a phase change material layer and a packaging layer, the packaging layer is arranged on the peripheral side of the phase change material layer, the phase change material layer comprises a heat insulation base material and a phase change material, and at least part of the phase change material is filled in the heat insulation base material; the strain of the composite phase change layer ranges from 8% to 20% when the stress borne by the composite phase change layer ranges from 0.5 MPa to 5 MPa. The composite heat insulation pad has relatively long service life and relatively good heat insulation performance, is applied to the battery, and has a good effect of preventing and slowing the thermal runaway of the battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a composite thermal insulation pad, a battery, and an electrical device. Background Art

[0002] With the development of new energy technologies, batteries are increasingly being used in the market, and people's requirements for battery performance are also increasing, such as the demand for energy density. However, battery cells with higher energy density have large residual energy after thermal runaway. When a battery cell thermally runs away, the heat from one battery cell will continue to transfer to adjacent battery cells, causing heat diffusion throughout the battery and causing damage to the entire battery. Therefore, how to mitigate battery thermal runaway is an urgent problem that needs to be solved. Summary of the Invention

[0003] Based on this, the present application provides a composite thermal insulation pad, a battery and an electrical device to solve the problem of how to prevent thermal runaway of the battery.

[0004] In a first aspect, an embodiment of the present application provides a composite thermal insulation pad, comprising:

[0005] A composite phase change layer includes a phase change material layer and an encapsulation layer, wherein the encapsulation layer is arranged on the outer peripheral side of the phase change material layer, the phase change material layer includes a thermal insulation substrate and a phase change material, and at least part of the phase change material is filled in the thermal insulation substrate; wherein the strain of the composite phase change layer when subjected to a stress of 0.5~5MPa is 8%~20%.

[0006] The composite thermal insulation pad mentioned in the present application, the encapsulation layer is arranged on the outer peripheral side of the phase change material layer to form a composite phase change layer, so that the phase change material layer in the composite phase change layer is physically isolated from the outside of the encapsulation layer, and the phase change material will not diffuse to the outside and lose before the encapsulation layer fails. Furthermore, the thermal insulation substrate can provide good support pressure resistance and thermal insulation performance for the composite phase change layer, and at the same time, the composite phase change layer also has certain compression performance, which can absorb battery expansion when the battery expands, thereby improving the service life and thermal insulation performance of the composite thermal insulation pad. The above-mentioned composite thermal insulation pad is applied to batteries and has a good effect of slowing down battery thermal runaway.

[0007] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0008] (1) The phase change material includes at least one of crystalline water and salt, phase change molten salt, paraffin, silicone oil, silica sol, aluminum sol, silica-alumina sol, fatty acid and alcohol;

[0009] (2) The thermal insulation substrate includes nano-ceramic fibers, and the nano-ceramic fibers include at least one of silica fibers, alumina fibers, zirconia fibers, alumina-silicon ceramic fibers, borosilicate ceramic fibers, boron-aluminum ceramic fibers, and zirconium-aluminum-silicon ceramic fibers;

[0010] (3) The thermal insulation substrate comprises nano-ceramic fibers, and the average diameter of the nano-ceramic fibers is 200-800 nm, and the thickness of the thermal insulation substrate is 1 mm-2 mm;

[0011] (4) In the phase change material layer, the mass ratio of the thermal insulation substrate to the phase change material is 1:(0.8-3);

[0012] (5) The phase change material layer further includes at least one of an infrared shielding agent, a flame retardant, and a thermal conductor; wherein the infrared shielding agent includes at least one of titanium dioxide, silicon oxide, and carbon powder; the flame retardant includes one or more of ammonium dihydrogen phosphate, tris(2,3-dibromopropyl) phosphate, thiophosphate triisocyanate, urea, ammonium pentaborate, ammonium bicarbonate, or melamine cyanurate; and the thermal conductivity of the thermal conductor is greater than 20 W / (mK);

[0013] (6) At least part of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; wherein the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material;

[0014] (7) A weak portion is provided on the area where the packaging layer forms the packaging cavity.

[0015] In some embodiments of the present application, at least a portion of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; wherein the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material; and the composite thermal insulation pad meets at least one of the following conditions:

[0016] (1) The wall material includes a polymer matrix, and the mass ratio of the polymer matrix to the core material is 1:(1.3-3);

[0017] (2) The Dv50 particle size of the phase change microcapsules is 0.5~8μm;

[0018] (3) The thermal conductivity of the wall material at 25°C is ≥ 0.32 W / mK;

[0019] (4) The melting point of the wall material is greater than 98°C;

[0020] (5) In the phase change material layer, the mass content of the phase change microcapsules is 50% to 70%.

[0021] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0022] (1) The mass ratio of the polymer matrix to the core material is 1:(1.3-1.6);

[0023] (2) The wall material further comprises ceramic particles filled in the polymer matrix, and the mass ratio of the polymer matrix to the ceramic particles is 3:(4-11);

[0024] (3) The Dv50 particle size of the phase change microcapsules is 0.5~8μm.

[0025] In some embodiments of the present application, the mass ratio of the polymer matrix to the ceramic particles is 3:(7~11).

[0026] In some embodiments of the present application, the phase change material includes a first paraffin wax having a melting point of 100-110°C and a second paraffin wax having a melting point of 110-120°C.

[0027] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0028] (1) The mass ratio of the first paraffin wax to the second paraffin wax is 33:(37-53);

[0029] (2) The molecular formula of the first paraffin is C m H 2m+2 , where 38≤m≤43;

[0030] (3) The molecular formula of the second paraffin is C w H 2w+2 , where 57≤w≤64.

[0031] In some embodiments of the present application, the phase change material further includes a third paraffin wax having a melting point of 63-72°C.

[0032] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0033] (1) The mass ratio of the third paraffin wax, the first paraffin wax and the second paraffin wax is (20-25): (34-57): (60-63);

[0034] (2) The molecular formula of the third paraffin is C n H 2n+2 , where 28≤n≤33.

[0035] In some embodiments of the present application, the composite thermal insulation pad further includes an outer thermal insulation layer disposed on at least one side of the outer periphery of the packaging layer.

[0036] In some embodiments of the present application, the strain of the outer thermal insulation layer when subjected to a stress of 0.5-5 MPa is 25%-70%.

[0037] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0038] (1) The outer insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K;

[0039] (2) The density of the outer insulation layer is 0.2~0.22g / cm 3 ;

[0040] (3) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating;

[0041] (4) The composite thermal insulation pad further includes a strain detection component, which is disposed within the outer thermal insulation layer or on the outer surface of the outer thermal insulation layer;

[0042] (5) The composite thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the encapsulation layer are connected via the adhesive layer;

[0043] (6) The composite thermal insulation pad further comprises a release adhesive layer, wherein the release adhesive layer comprises an adhesive layer and a release film, wherein the adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

[0044] In some embodiments of the present application, the composite thermal insulation pad meets at least one of the following conditions:

[0045] (1) The outer thermal insulation layer is a ceramic material layer;

[0046] (2) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film;

[0047] (3) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm;

[0048] (4) The thickness of the composite phase change layer is 1 mm to 6 mm;

[0049] (5) The thickness of the outer insulation layer is 0.5 mm to 8 mm;

[0050] (6) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer;

[0051] (7) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is 0.15-12:1;

[0052] (8) The outer heat insulation layer is provided on at least one of the two sides in the thickness direction of the composite phase change layer;

[0053] (9) The length and width of the outer heat-insulating layer are respectively adapted to the length and width of the composite phase change layer; or, at least one of the length and width of the outer heat-insulating layer is larger than the corresponding length or width of the composite phase change layer.

[0054] In some embodiments of the present application, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0055] The first thermal insulation layer and the second thermal insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first thermal insulation layer and the second thermal insulation layer;

[0056] The composite thermal insulation pad has a strain of 15% to 35% when subjected to a stress of 0.5 to 4 MPa.

[0057] In some embodiments of the present application, edges of the first thermal insulation layer and the second thermal insulation layer are connected to each other to form an assembly cavity, and the composite phase change layer is located in the assembly cavity.

[0058] In some embodiments of the present application, an edge of at least one side surface of at least one of the first thermal insulation layer and the second thermal insulation layer forms a convex portion, and the convex portion encloses and forms at least a portion of the assembly cavity.

[0059] In some embodiments of the present application, the packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

[0060] In some embodiments of the present application, the composite thermal insulation pad also includes a first packaging frame and a second packaging frame. The first packaging frame is arranged on one side of the first thermal insulation layer, and the second packaging frame is arranged on one side of the second thermal insulation layer. The first packaging frame and the second packaging frame cooperate to fix the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer.

[0061] In some embodiments of the present application, the encapsulation layer has an encapsulation margin portion, and the encapsulation margin portion is located between the first encapsulation frame and the second encapsulation frame.

[0062] In some embodiments of the present application, the first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in the limiting space formed by the first limiting groove and the second limiting groove.

[0063] In some embodiments of the present application, the outer surface of the first thermal insulation layer is flush with the outer surface of the first packaging frame, and / or the outer surface of the second thermal insulation layer is flush with the outer surface of the second packaging frame.

[0064] In some embodiments of the present application, the composite thermal insulation pad further includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

[0065] In a second aspect, the present application provides a battery comprising the above-mentioned composite thermal insulation pad.

[0066] In some embodiments, a plurality of battery cells are further included, and the composite thermal insulation pad is disposed between at least two adjacent battery cells.

[0067] In some embodiments, the composite thermal insulation pad is disposed between the large surfaces of two adjacent battery cells.

[0068] In a third aspect, the present application provides an electrical device comprising the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to one embodiment of the present application;

[0070] Figure 2 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0071] Figure 3 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0072] Figure 4 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0073] Figure 5 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0074] Figure 6 This is a schematic diagram of the three-dimensional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0075] Figure 7 for Figure 6 A schematic cross-sectional view of the composite thermal insulation pad shown in FIG.

[0076] Figure 8 for Figure 7 An exploded cross-sectional view of the composite thermal insulation pad shown;

[0077] Figure 9 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0078] Figure 10 for Figure 1 A schematic diagram of the front structure of the composite phase change layer of the composite thermal insulation pad shown;

[0079] Figure 11 This is a schematic structural diagram of a battery according to one embodiment of the present application;

[0080] Figure 12 This is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0081] Figure 13 is a schematic structural diagram of a battery cell in a battery according to one embodiment;

[0082] Figure 14 A schematic diagram of an electrical device using a battery as a power source according to one embodiment of the present application;

[0083] Figure 15 This is a thermal insulation performance curve of the composite thermal insulation pad prepared in Example 1;

[0084] Figure 16 This is a thermal insulation performance curve of the composite thermal insulation pad prepared in Example 2;

[0085] Figure 17 is a compressive stress-strain curve of a single composite phase change layer in Example 1;

[0086] Figure 18 is a compressive stress-strain curve diagram of the first thermal insulation layer alone in Example 1;

[0087] Figure 19 is a compressive stress-strain curve diagram of the composite thermal insulation pad as a whole in Example 1;

[0088] Figure 20 is an SEM image of the phase change material layer in the composite phase change layer of the composite thermal insulation pad of Example 18;

[0089] Figure 21 This is an EDS graph of the phase change material layer in the composite phase change layer in the composite thermal insulation pad of Example 18.

[0090] Description of reference numerals:

[0091] 10. Composite thermal insulation pad; 11. First thermal insulation layer; 12. Second thermal insulation layer; 13. Composite phase change layer; 131. Phase change material layer; 1311. Thermal insulation substrate; 1311a. One side edge of the thermal insulation substrate; 132. Encapsulation layer; 132a. Inner wall of the encapsulation cavity; 1321. Encapsulation margin; 1322. Weak portion; 141. First encapsulation frame; 142. Second encapsulation frame; 151. First adhesive layer; 152. Second adhesive layer; 16. Third thermal insulation layer; 17. Strain detection element; 172. External wires;

[0092] 20. Battery cell; 21. Housing; 22. Electrode assembly; 23. Cover plate;

[0093] 30. Battery;

[0094] 40. Electrical equipment. DETAILED DESCRIPTION

[0095] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0096] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0097] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0098] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0099] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0100] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0101] Currently, market developments indicate that batteries are becoming increasingly widely used. Batteries, particularly power batteries, are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles, as well as in other fields. As the application of power batteries continues to expand, market demand is also growing.

[0102] A battery cell is the smallest unit that makes up a battery. A battery can contain one or more battery cells, and multiple battery cells can be connected in series, parallel, or in a hybrid connection. Hybrid connection refers to multiple battery cells being connected in both series and parallel.

[0103] After multiple battery cells are interconnected and arranged in a certain order, they can be directly placed in a box to form a battery. Alternatively, multiple battery cells can be first assembled into a battery module, and then multiple battery modules are interconnected to form a whole, and finally the entire battery module is placed in a box to form a battery.

[0104] In order to solve the above-mentioned battery thermal runaway problem and reduce the damage and risk to the entire battery.

[0105] See also Figure 1 One embodiment of the present application provides a composite thermal insulation pad 10 , including a composite phase change layer 13 .

[0106] The composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132, wherein the encapsulation layer 132 is provided on the outer peripheral side of the phase change material layer 131. The phase change material layer 131 includes a heat-insulating substrate and a phase change material, and at least a portion of the phase change material is filled in the heat-insulating substrate. The strain of the composite phase change layer 13 when subjected to a stress of 0.5 to 5 MPa is 8% to 20%, and further, the strain when subjected to a stress of 0.5 to 4 MPa is 8% to 20%. Furthermore, the strain under the above stress is 10% to 20%, and further, 10% to 16%.

[0107] The stress-strain curves used in this article were obtained using the following method: A press was used to compress the sample at an inlet stress of 0.008 MPa at a rate of 2 mm / min until a certain pressure was reached. The tests were conducted at a temperature of 23°C ± 5°C, a relative humidity of 45% to 75%, and an atmospheric pressure of 86 kPa to 106 kPa.

[0108] The stress test equipment used is a Xiamen Yinghaoda pressure tester with a pressure range of 1-8 kN and a measurement area of 300 x 300 mm. Stress = load force / sample area.

[0109] Strain is the percentage change in thickness of a sample under stress relative to its initial thickness. The change in thickness under stress is measured by measuring the displacement relative to the initial position using a micrometer or pressure tester. The initial thickness of the sample is measured using a Mitutoyo 547-301 thickness gauge with an accuracy of ≤0.01mm. The test surfaces of the composite insulation pad and the Mitutoyo 547-301 thickness gauge must be parallel to the ground. Testing is performed at five locations, including the four corners and the center, with the average value of these five locations serving as the test value. Strain = displacement recorded by the micrometer or pressure tester / initial sample thickness.

[0110] According to the output load-displacement test raw data of the stress testing equipment, it is converted into stress-strain data and the compressive stress-strain curve is output.

[0111] In the composite thermal insulation pad 10, the encapsulation layer 132 is disposed on the outer peripheral side of the phase change material layer 131 to form a composite phase change layer 13. This physically isolates the phase change material layer 131 in the composite phase change layer 13 from the outer side of the encapsulation layer 132, thereby preventing the phase change material from diffusing to the outside and being lost before the encapsulation layer 132 fails. Furthermore, the thermal insulation substrate provides the composite phase change layer 13 with good support, pressure resistance, and thermal insulation properties. Furthermore, the composite phase change layer 13 also has certain compression properties, capable of absorbing battery expansion when the battery expands, thereby improving the service life and thermal insulation performance of the composite thermal insulation pad. The composite thermal insulation pad is applied to batteries and has a good effect in slowing down battery thermal runaway.

[0112] Due to the limitations of the structure, conventional technology can only use solid phase change materials as phase change materials. However, the heat absorption capacity of solid phase change materials is limited. The above-mentioned composite thermal insulation pad 10, due to its structure in which the phase change material layer 131 is arranged in the packaging cavity of the packaging layer 132, is physically isolated from the outer thermal insulation layer. Therefore, the phase change material of its phase change material layer 131 can be a solid phase change material, a liquid phase change material, or a solid-liquid mixed phase change material. Optionally, the phase change material includes but is not limited to crystalline water and salt, phase change molten salt, paraffin, silicone oil, silica sol, aluminum sol, silica aluminum sol, fatty acids, alcohols, and other substances that can undergo phase change and absorb heat. It has a wider range of applications and can therefore provide better thermal insulation performance.

[0113] In addition, because the phase change material of the phase change material layer 131 undergoes phase change, for example, the solid phase change material at room temperature turns into liquid after absorbing heat, the encapsulation layer 132 can also serve to isolate the liquid phase change material after phase change from the outer heat insulation layer.

[0114] In addition, some preparation processes inevitably cause the phase change material to contain moisture. The structure in which the phase change material layer 131 is disposed in the packaging cavity of the packaging layer 132 can prevent moisture overflow from causing adverse effects on the battery.

[0115] In some embodiments, the composite thermal insulation pad 10 may further include an outer thermal insulation layer, which is disposed on at least one side of the outer periphery of the encapsulation layer 132. On the one hand, the outer thermal insulation layer is disposed on at least one side of the outer periphery of the encapsulation layer 132, and the phase change material layer 131 in the encapsulation layer 132 can absorb the heat transferred from the outer thermal insulation layer to play a thermal insulation role. On the other hand, the encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 to form a composite phase change layer 13, so that the phase change material layer 131 in the composite phase change layer 13 is physically isolated from the outer thermal insulation layer, and thus before the encapsulation layer 132 fails, the phase change material will not diffuse into the inner portion of the outer thermal insulation layer to form a heat conduction path, and thus will not change the structure of the outer thermal insulation layer and its thermal insulation performance, thereby further improving the service life and thermal insulation performance of the composite thermal insulation pad.

[0116] In some embodiments, the outer insulation layer exhibits a strain of 25% to 70% when subjected to a stress of 0.5 to 5 MPa. Furthermore, the strain of the sample is 25% to 70% when subjected to a stress of 0.5 to 3 MPa, and even more preferably, the strain of the sample is 29% to 57% when subjected to a stress of 0.5 to 2.8 MPa. The outer insulation layer has a certain degree of compressibility, capable of absorbing battery expansion, thereby further improving the service life and thermal insulation performance of the composite insulation mat.

[0117] Furthermore, the outer heat insulation layer may be provided on at least one of the two sides in the thickness direction of the composite phase change layer 13 .

[0118] For example, the outer heat insulation layer may be provided on one side or two opposite sides of the encapsulation layer 132 in the thickness direction of the composite phase change layer 13 .

[0119] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer 11 and a second thermal insulation layer 12, and the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged on both sides of the composite phase change layer 13 in the thickness direction, so that the composite phase change layer 13 is sandwiched between the first thermal insulation layer 11 and the second thermal insulation layer 12. In other words, the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are stacked in sequence. The encapsulation layer 132 is arranged on the outer peripheral side of the phase change material layer 131 and constitutes an encapsulation cavity, and the phase change material layer 131 is arranged in the encapsulation cavity. Further, the encapsulation cavity is a closed cavity. Furthermore, the strain of the composite thermal insulation pad 10 when subjected to a stress of 0.5~4MPa is 15%~35%, further, the strain when subjected to a stress of 0.5~3MPa is 15%~35%, and further, 15%~30%. In this way, the composite thermal insulation pad 10 has both good compression performance and thermal insulation performance, so that it can be used in the thermal insulation structure of the battery with good thermal insulation performance, preventing the spread of thermal runaway, and absorbing battery expansion, reducing the risks brought by battery expansion.

[0120] The above-mentioned composite thermal insulation pad 10, on the one hand, is provided with a first thermal insulation layer 11 and a second thermal insulation layer 12 at the same time, which can play a good thermal insulation role; on the other hand, the composite phase change layer 13 is provided between the first thermal insulation layer 11 and the second thermal insulation layer 12, and the composite phase change layer 13 can absorb the heat transferred from the thermal insulation layers on both sides, thereby further improving the thermal insulation performance of the above-mentioned composite thermal insulation pad 10.

[0121] It is understandable that in other examples, the outer insulation layer may include only the first insulation layer 11 or only the second insulation layer 12 , and its material and thickness may be the same or similar to those of the first insulation layer 11 or the second insulation layer 12 .

[0122] In some embodiments, the phase change material includes a first paraffin wax having a melting point of 100-110°C.

[0123] In some embodiments, the phase change material further includes a second paraffin wax having a melting point of 110-120°C.

[0124] Furthermore, the mass ratio of the first paraffin wax to the second paraffin wax is 33:(37-53). By combining the two paraffin waxes in this specific mass ratio, the phase change temperature of the phase change material layer can be controlled to be approximately 105°C to 110°C, making it particularly suitable for battery cells with a thermal runaway temperature below 600°C, such as lithium iron phosphate batteries used in energy storage, which have a relatively milder thermal runaway temperature than NCM batteries.

[0125] Furthermore, the molecular formula of the first paraffin is C m H 2m+2 , where 38≤m≤43.

[0126] Furthermore, the molecular formula of the second paraffin is C w H 2w+2 , where 57≤w≤64.

[0127] In some embodiments, the phase change material further comprises a third paraffin wax having a melting point of 63-72°C.

[0128] Furthermore, the mass ratio of the third paraffin wax, the first paraffin wax, and the second paraffin wax is (20-25):(34-57):(60-63). By combining the three paraffin waxes in a specific mass ratio, the phase change temperature of the phase change material layer can be controlled at approximately 100°C. This is particularly suitable for batteries with a self-heating temperature of approximately 110°C, such as NCM cells. NCM cells experience a rapid temperature rise after thermal runaway. Therefore, the phase change temperature of the phase change material layer is controlled at approximately 100°C. When the first cell thermally runs away, gradient melting occurs due to the presence of different ratios of paraffin components in the phase change material layer. This allows the cold surface temperature of the composite thermal insulation pad to be controlled below 100°C, keeping the large surface temperature of the adjacent cell in thermal runaway below 100°C. These adjacent cells will not undergo self-heating reactions, and the composite thermal insulation pad can effectively prevent thermal runaway.

[0129] Furthermore, the molecular formula of the third paraffin is C n H 2n+2 , where 28≤n≤33.

[0130] See also Figure 2In some embodiments, the composite thermal insulation pad 10 further includes an adhesive layer, and the outer thermal insulation layer is connected to the encapsulation layer 132 via the adhesive layer. Furthermore, the adhesive layer includes a first adhesive layer 151 and a second adhesive layer 152. The first thermal insulation layer 11 is connected to the encapsulation layer 132 via the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 via the second adhesive layer 152. In this way, the first thermal insulation layer 11, the composite phase change layer 13, and the second thermal insulation layer 12 of the composite thermal insulation pad 10 are connected and fixed in the thickness direction via the adhesive layer.

[0131] Furthermore, the first adhesive layer 151 and the second adhesive layer 152 are each independently made of a silicone adhesive layer, and each independently has a thickness of 0.04 to 0.06 mm. The silicone adhesive layer is resistant to high temperatures and has high structural strength. The peeling force of the resulting composite thermal insulation pad is greater than 10 N / cm. The peeling force can be measured by pulling the two sides of the composite thermal insulation pad with a tensile gauge and applying a force perpendicular to the composite thermal insulation pad at 90 degrees to the two sides of the composite thermal insulation pad. The tensile gauge will display the magnitude of the pulling force when the composite thermal insulation pad is peeled off, and the peeling force can be obtained based on the magnitude of the pulling force.

[0132] In some embodiments, the composite thermal insulation pad 10 further includes a release adhesive layer (not shown). The release adhesive layer comprises a third adhesive layer and a release film. The third adhesive layer is disposed on the outer surface of the outer insulation layer (i.e., the first insulation layer 11 and / or the second insulation layer 12), and the release film is disposed on the outer surface of the third adhesive layer. Thus, when the composite thermal insulation pad 10 needs to be secured to a desired location, such as a battery cell, the release film on the release adhesive layer is removed and the composite thermal insulation pad 10 is simply and conveniently secured to the desired location via bonding with the third adhesive layer, thereby securing the composite thermal insulation pad 10.

[0133] As an example, the aforementioned release adhesive layer is provided on the outer surfaces of the first insulation layer 11 and the second insulation layer 12 of the composite thermal insulation mat 10. During use, the composite thermal insulation mat 10 can be bonded and fixed to two objects, for example, two adjacent battery cells, using the release adhesive layers on both sides, so that the composite thermal insulation mat 10 is positioned between the two adjacent battery cells.

[0134] See also Figure 3 The composite thermal insulation pad 10 further includes a strain detection member 17, which is disposed in the outer thermal insulation layer. Further, the strain detection member 17 is disposed within the outer thermal insulation layer, or on the outer surface of the outer thermal insulation layer.

[0135] It is understood that the strain detection element 17 may be disposed within the outer thermal insulation layer, including but not limited to a portion or the entirety of the strain detection element 17 being located within the outer thermal insulation layer. The entirety of the strain detection element 17 being located within the outer thermal insulation layer includes but is not limited to a portion of the surface of the strain detection element 17 being flush with the outer thermal insulation layer, i.e., such portion of the surface is uncovered by the thermal insulation layer and is exposed, and also includes the entirety of the surface of the strain detection element 17 being covered by the outer thermal insulation layer, i.e., the entirety of the strain detection element 17 being located within the outer thermal insulation layer.

[0136] The strain detector 17 is a component used to detect stress parameters. Generally, it includes a flexible layer and a strain detection element layer disposed on the flexible layer. The flexible layer can deform synchronously with the insulation layer on which it is located. The strain detection element layer can convert the deformation of the flexible layer into an electrical signal output, such as a voltage signal. In this way, the pressure parameters of the forehead support and the composite insulation pad 10 can be determined based on the electrical signal output by the strain detector 17, that is, the stress experienced by the composite insulation pad 10 can be monitored. For example, the volume of a battery cell expands during use, which causes the pressure between adjacent cells to change. Therefore, when the composite insulation pad 10 is used in a battery, the strain detector 17 can be used to determine the expansion state of the battery during use. In addition, the encapsulation layer 132 of the composite insulation pad 10 also causes pressure changes between adjacent cells before and after failure. Therefore, the strain detector 17 can also determine whether the encapsulation layer 132 is crushed and fails during battery use. In this way, the strain detector 17 provided in the composite insulation pad 10 can accurately determine the state of the battery during use.

[0137] Specifically, the strain detection element 17 may be provided in at least one of the first thermal insulation layer 11 and the second thermal insulation layer 12 .

[0138] In some examples, strain is generated by applying pressure to the composite thermal insulation pad 10. For example, in the process of strain from 0 to point A, the greater the strain, the greater the stress detected by the strain detection member 17. This is the deformation state of the packaging layer 132 in the composite thermal insulation pad 10 before failure. When point A is reached, pressure is continued to be applied, the strain continues to increase, but the stress detected by the strain detection member 17 decreases. This is because the external pressure is too large, causing the packaging layer 132 to collapse and fail, which in turn causes a sudden change in stress and rapid stress relief. After that, as the strain increases, the stress continues to increase. In this way, the state of the composite thermal insulation pad 10 can be known by the stage of the stress curve detected by the strain detection member 17. When applied to batteries, the state of the battery cells adjacent to the composite thermal insulation pad 10 can also be known.

[0139] In such Figure 1In the specific example, the strain detection element 17 is provided in the second thermal insulation layer 12, and the strain detection element 17 is entirely located within the second thermal insulation layer 12. It is understood that the strain detection element 17 may also be provided in the first thermal insulation layer 11, or in both the first thermal insulation layer 11 and the second thermal insulation layer 12.

[0140] Furthermore, the strain sensing element 17 has a first surface that is distal to the composite phase change layer 13, and the outer thermal insulation layer on which the strain sensing element 17 is mounted has a second surface that is distal to the composite phase change layer 13. The distance between the first and second surfaces is ≥ 0.3 mm, and can be selected from 0.3 mm to 0.5 mm, and more preferably from 0.3 mm to 0.45 mm. Both the first and second surfaces are outer surfaces that are distal to the composite phase change layer 13. This allows the composite thermal insulation pad to protect the strain sensing element 17 while maintaining its sensitivity.

[0141] It can be understood that the strain detection element 17 is provided on the surface of the outer heat insulation layer, which may be the surface opposite to the composite phase change layer 13 or the surface opposite to the composite phase change layer 13 .

[0142] Optionally, the strain detector 17 is positioned on the outer surface of the outer insulation layer, enabling a more rapid response to stress changes. Furthermore, the composite insulation mat 10 may also include a waterproof protective film (not shown) positioned on the outer surface of the strain detector 17 to protect it from moisture and extend its service life.

[0143] Furthermore, the strain detector 17 also has an external wire 172, which is led out from one side of the corresponding insulation layer for connection to the low-voltage connection line in the battery. Optionally, the external wire 172 is led out from the shorter side of the corresponding insulation layer for easier wiring.

[0144] It can be understood that, generally, the strain detection element 17 also has two external wires 172 , through which the strain electrical signal converted from the deformation can be output to the outside.

[0145] In some embodiments, the ratio of the thickness of the strain detection member 17 to the thickness of the outer heat insulation layer is 1:(500-10).

[0146] Furthermore, the thickness of the strain detection element 17 is 10-50 μm. As an example, the thickness of the strain detection element 17 may be 13 μm. It is understood that the thickness here refers to the sum of the thicknesses of the flexible layer and the strain detection element layer.

[0147] like Figure 3As shown, the first thermal insulation layer 11 and the second thermal insulation layer 12 are physically separated by the composite phase change layer 13 . In other words, the edges between the first thermal insulation layer 11 and the second thermal insulation layer 12 are not connected to each other.

[0148] In some embodiments, the length and width of the outer thermal insulation layer are respectively adapted to the length and width of the composite phase change layer 13. In other embodiments, at least one of the length and width of the outer thermal insulation layer is greater than the corresponding length or width of the composite phase change layer 13.

[0149] See also Figure 4 In some embodiments, the edges of the first and second thermal insulation layers 11, 12 are connected to form an assembly cavity, within which the composite phase change layer 13 is located. This structural arrangement allows the composite phase change layer 13 to be located within the first and second thermal insulation layers 11, 12, reducing the risk of the composite phase change layer 13 falling off.

[0150] Furthermore, the edge of at least one side surface of at least one of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portion encloses at least part of the assembly cavity. As an example, the edge of at least one side surface of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portions of the two are arranged relative to each other and enclose to form an assembly cavity. Figure 4 In a specific example, convex portions are formed on the four edges of one side surface of the first thermal insulation layer 11 and the second thermal insulation layer 12, and the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged opposite to each other and enclosed to form an assembly cavity.

[0151] Generally, the side of the phase change material layer 131 is encapsulated by an encapsulation film, and there is an encapsulation margin on the side, for example, Figure 8 That is, the encapsulation layer 132 has an encapsulation margin 1321. When the composite phase change layer 13 is disposed inside the first thermal insulation layer 11 and the second thermal insulation layer 12, the encapsulation margin is folded and located in the assembly cavity.

[0152] As an example, the encapsulation layer 132 has an encapsulation margin on all four sides.

[0153] See also Figure 5 In some embodiments, the composite thermal insulation pad 10 further includes a third thermal insulation layer 16, and a composite phase change layer 13 is also provided between the second thermal insulation layer 12 and the third thermal insulation layer 16. Furthermore, the composite thermal insulation pad 10 may further include more thermal insulation layers, and the composite phase change layer 13 may also be provided between the adjacent thermal insulation layers.

[0154] Furthermore, the selection range of materials and thicknesses of the third thermal insulation layer 16 and other thermal insulation layers can be the same as that of the first thermal insulation layer 11 and the second thermal insulation layer 12; the specific materials and specific thicknesses can be the same or different.

[0155] See also Figure 6 and Figure 7 In some embodiments, the composite thermal insulation pad 10 also includes a first packaging frame 141 and a second packaging frame 142. The first packaging frame 141 is arranged on one side of the first thermal insulation layer 11, and the second packaging frame 142 is arranged on one side of the second thermal insulation layer 12. The first packaging frame 141 and the second packaging frame 142 cooperate to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12.

[0156] Furthermore, the first packaging frame 141 and the second packaging frame 142 are each independently a rubber frame or a silicone frame. In other words, the first packaging frame 141 and the second packaging frame 142 are each independently made of rubber or silicone. Furthermore, the first packaging frame 141 and the second packaging frame 142 are both shaped like a truncated frame, such as a silicone truncated frame.

[0157] In such Figure 7 and Figure 8 In the example shown, the first packaging frame 141 has a first limiting groove (not shown), and the second packaging frame 142 has a second limiting groove (not shown), and the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can limit the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 in the thickness direction and the radial direction of the composite thermal insulation pad 10, thereby improving the structural stability of the composite thermal insulation pad 10. Among them, the radial direction of the composite thermal insulation pad 10 refers to the direction from the center of the composite thermal insulation pad 10 to the edge of the composite thermal insulation pad 10. Further, at this time, the packaging margin portion 1321 of the packaging layer 132 can be located between the first packaging frame 141 and the second packaging frame 142, such as Figure 8 As shown, the package margin portion 1321 is pressed in the middle by the first package frame 141 and the second package frame 142 .

[0158] It can be understood that when the above-mentioned first packaging frame 141 and second packaging frame 142 and the above-mentioned first thermal insulation layer 11 and second thermal insulation layer 12 that can form an assembly cavity are provided at the same time, the packaging margin portion 1321 of the packaging layer 132 can pass through between the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 and be located between the first packaging frame 141 and the second packaging frame 142, or the packaging margin portion 1321 of the packaging layer 132 can also be folded and located in the assembly cavity.

[0159] See also Figure 9In other embodiments, the outer surface of the first thermal insulation layer 11 is flush with the outer surface of the first packaging frame 141, and / or the outer surface of the second thermal insulation layer 12 is flush with the outer surface of the second packaging frame 142. This can minimize the thickness of the composite thermal insulation pad 10 and reduce the space it occupies while providing better thermal insulation performance.

[0160] As an example, based on the aforementioned first adhesive layer 151 and second adhesive layer 152, the aforementioned first packaging frame 141 and second packaging frame 142 can be further used to secure the first thermal insulation layer 11, the composite phase change layer 13, and the second thermal insulation layer 12 around their perimeters, thereby improving the structural stability of the composite thermal insulation pad 10. Furthermore, in this case, there is no need for the packaging frame to secure the thickness direction, so that the outer surface of the first thermal insulation layer 11 can be flush with the outer surface of the first packaging frame 141, and the outer surface of the second thermal insulation layer 12 can be flush with the outer surface of the second packaging frame 142.

[0161] It can be understood that in some embodiments, the first thermal insulation layer 11, the composite phase change layer 13, the second thermal insulation layer 12, and the third thermal insulation layer 16 can be connected by the above-mentioned adhesive layer, or by the above-mentioned packaging frame, or by both the above-mentioned adhesive layer and the packaging frame, or by neither, for example, the first thermal insulation layer 11 can be directly formed on the packaging layer 132 of the composite phase change layer 13.

[0162] Furthermore, the first thermal insulation layer 11 , the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently include at least one of thermal insulation felt and thermal insulation coating.

[0163] Furthermore, when any of the aforementioned thermal insulation layers includes both a thermal insulation felt and a thermal insulation coating, the thermal insulation coating may be optionally disposed on a side closer to the composite phase change layer 13. Specifically, the thermal insulation coating is disposed on the surface of the encapsulation layer 132 of the composite phase change layer 13, and the thermal insulation felt is disposed on a side further away from the composite phase change layer 13. In other words, the thermal insulation coating is formed directly on the surface of the encapsulation layer 132 and is located between the encapsulation layer 132 and the thermal insulation felt.

[0164] For example, Figure 1 、 Figure 2 and Figure 5 In the example, the first thermal insulation layer 11 and the second thermal insulation layer 12 are thermal insulation felt, and the third thermal insulation layer 16 is also thermal insulation felt. In other examples, the first thermal insulation layer 11 and the second thermal insulation layer 12 may also be thermal insulation coatings. In comparison, the thickness of the thermal insulation coating is thinner, and the overall thickness of the composite thermal insulation pad is thinner, and the required space is relatively smaller. The thermal insulation layer of the composite thermal insulation pad 10 can optionally adopt a thermal insulation coating, or a composite of a thermal insulation coating and ceramic felt, which can take into account both a smaller occupied space and better thermal insulation performance.

[0165] by Figure 1For example, when a strain detector 17 is provided in the second thermal insulation layer 12, a groove for accommodating the strain detector 17 can be first opened in the second thermal insulation layer 12. After the strain detector 17 is placed in the groove, thermal insulation felt can be filled to cover the strain detector 17. Specifically, the strain detector 17 can be fixed to the thermal insulation felt by an adhesive layer.

[0166] For example, in Figure 4 In the example shown, the first insulation layer 11 and the second insulation layer 12 are insulation felts, and the assembly cavity thereon can be integrally formed when the insulation felt is formed, or can be formed by grooving after the insulation felt is formed.

[0167] It is understood that the thermal insulation felt can be connected to the composite phase change layer 13 via the aforementioned adhesive layer or encapsulation frame. The thermal insulation coating can be formed directly on the encapsulation layer 132 in the composite phase change layer 13. As an example, the thermal insulation coating can be formed by coating the encapsulation layer 132 of the composite phase change layer 13 with a slurry and then drying it to form a coating.

[0168] Furthermore, the thermal insulation felt may be a ceramic thermal insulation felt; further, the thermal insulation coating may be a ceramic thermal insulation coating.

[0169] In some embodiments, the first thermal insulation layer 11, the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently meet the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K.

[0170] In some embodiments, the density of the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 16 are independently 0.2-0.22 g / cm 3 .

[0171] In some embodiments, the outer insulation layer is a ceramic material layer.

[0172] In some embodiments, the thickness ratio of the composite phase change layer 13 to the outer thermal insulation layer is 0.15-12:1, further 0.5-8:1. For example, it can be 0.15:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, or 12:1.

[0173] Furthermore, the thickness of the outer heat insulation layer is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm; it can be optionally 1 mm to 8 mm.

[0174] In this article, the following method can be used to test the thickness of composite insulation pads. The equipment used is a Mitutoyo 547-301 thickness gauge with an accuracy of ≤0.01mm. The composite insulation pad and the Mitutoyo 547-301 thickness gauge must be parallel to the ground during testing. Testing is performed at five locations, including the four corners and the center, with the average value of these five locations being used as the test value. For example, the thickness of the outer insulation layer is measured.

[0175] In some embodiments, the first thermal insulation layer 11 is a ceramic material layer. Further, the thickness of the first thermal insulation layer 11 is 0.5 mm to 8 mm, and as an example, can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; optionally, 1 mm to 8 mm.

[0176] In some embodiments, the second thermal insulation layer 12 is a ceramic material layer. Further, the thickness of the second thermal insulation layer 12 is 0.5 mm to 8 mm, and as an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; optionally, it can be 1 mm to 8 mm.

[0177] The material of the "ceramic material layer" in this application includes, but is not limited to, at least one of ceramic oxides, ceramic nitrides, and ceramic carbides. Among them, ceramic oxides include, but are not limited to, silicon oxide and aluminum oxide; ceramic nitrides include, but are not limited to, silicon nitride; and ceramic carbides include, but are not limited to, silicon carbide.

[0178] In some examples, the ceramic material layer may be a stack of one or more of a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, and a silicon carbide layer.

[0179] Furthermore, the ceramic insulation felt may be a silica aerogel ceramic felt. As an example, the silica aerogel ceramic felt may be prepared by inorganic fiber reinforcement technology to prepare aerogel materials, through impregnation sol, gel, solvent replacement and supercritical drying processes.

[0180] In some embodiments, the thickness of the phase change material layer 131 accounts for 70% to 96% of the total thickness of the composite phase change layer 13, and can be optionally 86% to 96%. As an example, the thickness can be 70%, 75%, 80%, 85%, 86%, 90%, 92%, 95%, or 96%.

[0181] In some embodiments, the thickness of the composite phase change layer 13 is 1 mm to 6 mm, and can be 1 mm to 4 mm. As an example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, or 6 mm. It can be 1.5 mm to 3.5 mm.

[0182] In some embodiments, the thickness of the encapsulation layer 132 is 0.1 mm to 0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and can be optionally 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0183] In some embodiments, the packaging layer 132 is an aluminum-plastic film or a polymer packaging film.

[0184] Furthermore, the polymer packaging film may be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0185] See also Figure 10 In some embodiments, a weak portion is defined in the area of the packaging layer 132 that forms the packaging cavity. Because the weak portion is located in a vulnerable area, when the composite phase-change layer 13 absorbs a large amount of heat, the phase-change material in the phase-change material layer 131 undergoes a phase change, causing the packaging layer 132 to bulge. This allows the packaging layer 132 to rupture promptly at the weak portion in the event of thermal runaway, further reducing the damage to the battery as a whole.

[0186] It can be understood that the weak portion 1322 on the encapsulation layer 132 is a relatively weak area on the encapsulation layer 132 .

[0187] In some embodiments, the weak portion 1322 is a region of relatively thin thickness and / or relatively weak material strength. In other words, the weak portion 1322 can be a region of relatively thin thickness but constant material strength, which can be formed by locally thinning the encapsulation layer 132. The weak portion 1322 can also be a region of relatively constant thickness but relatively weak material strength, which can be formed by locally weakening the material strength of the encapsulation layer 132, for example, by using materials of different strengths. Alternatively, the weak portion 1322 can be a region of relatively thin thickness and relatively weak material strength. It should be understood that the material strength here refers to the strength of the material itself.

[0188] Furthermore, the weak portion 1322 is a notch area formed on the packaging layer 12. It can be understood that the notch area is formed by thinning the surface of the packaging layer by embossing, and the thickness of the notch area is relatively thin.

[0189] Furthermore, the weak portion 1322 can be disposed on the outside or inside of the encapsulation layer 132. The outside refers to the surface of the encapsulation layer 132 away from the phase change material layer 131, and the inside refers to the surface of the encapsulation layer 132 close to the phase change material layer 131.

[0190] Furthermore, the depth of the weak portion 1322 accounts for 15% to 50% of the thickness of the encapsulation layer 132, for example, 15%, 20%, 30%, 35%, 40%, 45%, or 50%. Controlling this thickness ratio allows the encapsulation layer 132 to provide both good isolation when no package breakage is required and good, timely package breakage in the event of thermal runaway.

[0191] Furthermore, the aluminum-plastic film includes an aluminum foil layer and plastic film layers arranged on both surfaces of the aluminum foil layer.

[0192] Furthermore, when encapsulation layer 132 is an aluminum-plastic film, the weak portion extends from the surface of the aluminum-plastic film to 30% to 60% of the thickness of the aluminum foil layer, for example, 30%, 40%, 50%, or 60%. The weak portion is controlled to penetrate the aluminum foil layer without penetrating the aluminum foil layer, and is further controlled to penetrate 30% to 60% of the thickness of the aluminum foil layer. This ensures that encapsulation layer 132 provides both better isolation when rupture is not necessary and better, more timely rupture in the event of thermal runaway.

[0193] The plastic film layer in the aluminum-plastic film may include but is not limited to at least one of a polypropylene layer, a nylon layer and a polyester layer.

[0194] In some examples, encapsulation layer 132 includes a polypropylene layer, an aluminum foil layer, a nylon layer, and a polyester layer stacked from inside to outside. Specifically, the thicknesses of the polypropylene layer, the aluminum foil layer, the nylon layer, and the polyester layer are 80 μm, 40 μm, 15 μm, and 6 μm, respectively. The weak portion 1322 may extend from one side of the polyester layer to half the thickness of the aluminum foil layer.

[0195] It is worth noting that at least a portion of the phase change material is filled in the pores of the thermal insulation substrate. The phase change material may be completely filled in the pores of the thermal insulation substrate, or only partially filled in the pores of the thermal insulation substrate. For example, a portion of the phase change material may be free from the thermal insulation substrate.

[0196] In some embodiments, in addition to the phase change material, the phase change material layer may also include at least one of an infrared shielding agent, a flame retardant, and a thermal conductor. The infrared shielding agent includes at least one of titanium dioxide, silicon oxide, and carbon powder; the flame retardant includes one or more of ammonium dihydrogen phosphate, tris(2,3-dibromopropyl) phosphate, thiophosphate triisocyanate, urea, ammonium pentaborate, ammonium bicarbonate, or melamine cyanurate; and the thermal conductor has a thermal conductivity greater than 20 W / (mK). Furthermore, the thermal conductor may include at least one of copper, silver, carbon black, graphene, aluminum nitride, boron nitride, silicon nitride, and magnesium oxide. The phase change material layer can be obtained by forming a mixed solution of the phase change material and at least one of the infrared shielding agent, flame retardant, and thermal conductor, immersing the thermal insulation substrate in the mixed solution, and then drying or heat-insulating the solution.

[0197] Furthermore, in phase change material layer 131, the mass ratio of the thermal insulation substrate to the phase change material is 1:(0.8-3). As an example, the mass ratio can be 1:0.8, 1:1, 1:1.2, 1:1.5, 1:2, 1:2.5, or 1:3. The thermal insulation substrate can be a ceramic substrate, such as ceramic fiber felt.

[0198] Furthermore, in some examples, the phase change material is directly filled in the pores of the thermal insulation substrate. Furthermore, in the phase change material layer 131, the mass proportion of the phase change material is 53% to 67%, for example, 53%, 60%, or 67%.

[0199] In other examples, the phase change material can also be filled into the pores of the thermal insulation substrate in the form of phase change microcapsules. It is understood that the same thermal insulation substrate can also include two phase change material states: one in which the phase change material is directly filled into the pores of the thermal insulation substrate, and the other in which the phase change material is filled into the pores of the thermal insulation substrate in the form of phase change microcapsules. Furthermore, in the phase change material layer 131, the mass content of the phase change microcapsules is 50% to 70%, for example, 50%, 60%, or 70%.

[0200] It is understood that the phase change material layer 131 can be obtained by soaking a porous thermal insulation substrate such as ceramic fiber felt in a liquid phase change material, for example, by soaking it in a molten phase change material and then cooling it, or by soaking it in a phase change material solution and then drying or heat-insulating it. In addition to absorbing heat, the phase change material layer 131 can also provide thermal insulation. When the phase change material vaporizes and breaks through the encapsulation layer 132, that is, the composite thermal insulation pad 10 fails, the thermal insulation substrate in the phase change material layer 131 can continue to provide thermal insulation. In other words, the phase change material directly fills the pores of the thermal insulation substrate.

[0201] Furthermore, the above-mentioned phase change material solution may also be added with at least one of a flame retardant and a thermal conductive material to improve its flame retardant and thermal conductive properties. Among them, the flame retardant includes but is not limited to at least one of urea and ammonium bicarbonate, and the thermal conductive material includes but is not limited to at least one of copper powder, carbon black, and silver powder. The thermal insulation substrate is then immersed in the above-mentioned phase change material solution and then subjected to heat preservation treatment. In other embodiments, at least part of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. In other words, the pores of the thermal insulation substrate of the phase change material layer 131 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes a phase change material. It can be understood that in some examples, the pores of the thermal insulation substrate can also be directly filled with phase change material and the above-mentioned phase change microcapsules at the same time.

[0202] The above-mentioned phase change material layer 131 can be obtained by dispersing phase change microcapsules in a solvent to obtain a phase change microcapsule dispersion, then immersing a thermal insulation substrate in the phase change microcapsule dispersion to fill the phase change microcapsules in the pores of the thermal insulation substrate, and drying to remove the solvent in the phase change microcapsule dispersion.

[0203] In this way, the phase change microcapsules in the phase change material layer 131 absorb heat. When the battery cell thermally runs away, the phase change material in the adjacent composite thermal insulation pad 10 vaporizes and breaks the packaging layer 132, that is, the composite thermal insulation pad 10 fails. At this time, the thermal insulation substrate in the phase change material layer 131 can continue to play a thermal insulation role.

[0204] Furthermore, the wall material includes a polymer matrix. Furthermore, the mass ratio of the polymer matrix to the core material is 1:(1.3-3), optionally 1:(1.3-1.6). As examples, the mass ratio of the polymer matrix to the core material can be 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:2, 1:2.5, or 1:3. This can further improve the pressure resistance of the phase change microcapsules. As an example, the polymer matrix can be a phenolic resin matrix. It is understood that the polymer matrix is not limited to this and can also be any of polyacrylonitrile resin, melamine formaldehyde resin, and phenolic resin polymer.

[0205] Furthermore, the wall material also includes ceramic particles filled in a polymer matrix. Furthermore, the mass ratio of polymer matrix to ceramic particles is 3:(4-11), and can optionally be 3:(7-11). As an example, the mass ratio of polymer matrix to ceramic particles can be 3:4, 3:5, 3:6, 3:7, 3:8, 3:9, 3:10, or 3:11. By controlling the mass content of ceramic particles in the wall material to a high level, the wall material's pressure resistance and thermal insulation capabilities can be improved.

[0206] Furthermore, the Dv50 particle size of the phase change microcapsule is 0.5-8 μm, and can be 5-8 μm. As an example, the Dv50 particle size of the phase change microcapsule can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, or 8 μm.

[0207] The Dv50 particle size, or volume average particle size Dv50, represents the particle size corresponding to when the cumulative volume distribution percentage of the particles reaches 50%, and can be measured using methods known in the art, for example, using a laser particle size analyzer (e.g., MalvernMaster Size 3000).

[0208] Furthermore, the thermal conductivity of the wall material at 25° C. is ≥0.32 W / mK. Such a wall material has a good thermal conductivity and can better conduct heat to the phase change material inside it.

[0209] Furthermore, the melting point of the wall material is greater than 98° C. The high melting point of the wall material can maintain the structural stability of the microcapsule within the phase change temperature range of the phase change material.

[0210] The materials for the thermal insulation substrate and ceramic particles described herein are within the same range as those for the ceramic material layer. In some examples, the thermal insulation substrate is a ceramic fiber mat. Ceramic fiber mats, with ceramic fibers as their core skeleton, not only effectively wet liquid phase change materials but also exhibit low thermal conductivity, excellent high-temperature resistance (1280°C), transient thermal shock resistance, flame retardancy, and mechanical properties. They also exhibit no pulverization, are flexible and resilient, and are compatible with battery pack manufacturing processes.

[0211] In some examples, the thermal insulation substrate includes nano-ceramic fibers, which include at least one of silica fibers, alumina fibers, zirconia fibers, alumina-silicon ceramic fibers, borosilicate ceramic fibers, boron-alumina ceramic fibers, and zirconium-alumina-silicon ceramic fibers.

[0212] Furthermore, the average diameter of the nano-ceramic fibers is 200-800 nm, and the thickness of the thermal insulation substrate is 1 mm-2 mm.

[0213] In some examples, the ceramic particles include, but are not limited to, at least one of boron nitride particles, silicon nitride particles, silicon carbide particles, and silicon dioxide particles. Furthermore, the ceramic particles have a Dv50 of 60 to 90 nm. For example, the Dv50 of the ceramic particles can be any value among 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 83 nm, 85 nm, and 90 nm, or between any two values. Silicon dioxide particles of this specific particle size facilitate doping and uniform dispersion in the substrate.

[0214] Phase-change microcapsules can be produced by in-situ polymerization, where the wall material coats the core material. In some examples, the preparation method for phase-change microcapsules includes the following steps: dispersing ceramic particles in water to form an aqueous phase; heating the phase-change material to a molten state to form an oil phase; mixing the aqueous and oil phases and stirring to form a Pickering emulsion; adding the raw materials required to prepare the polymer matrix of the wall material (e.g., a water-soluble polymer monomer or prepolymer aqueous solution) to the Pickering emulsion; and polymerizing the mixture under stirring at room temperature to form a water-insoluble condensation polymer (i.e., the polymer matrix) with a cross-linked three-dimensional network structure at the emulsion interface.

[0215] The polymer matrix of the above-mentioned material has better compatibility with phase change materials such as paraffin wax, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of the phase change microcapsules.

[0216] Please continue reading Figure 10It can be understood that the phase-change material layer 131 includes the aforementioned thermal insulation substrate 1311 and the phase-change material filling the pores of the thermal insulation substrate 1311. The phase-change material layer 131 is located within the packaging cavity. In other words, the thermal insulation substrate 1311 is also located within the packaging cavity. Furthermore, a gap exists between at least one side edge 1311a of the thermal insulation substrate 1311 located within the packaging cavity and the inner wall 132a of the packaging cavity. The weak portion 1322 is provided on the packaging layer 132 and is located between the edge 1311a of the thermal insulation substrate 1311 and the inner wall 132a of the packaging cavity.

[0217] It can be understood that since the encapsulation layer 132 is provided on the outer surface of the phase change material layer 131 and forms an encapsulation cavity, the encapsulation layer 132 includes a first region in contact with the first thermal insulation layer 11, a second region in contact with the second thermal insulation layer 12, and a third region connecting the first and second regions. The weak portion 1322 is provided in the first and / or second regions of the encapsulation layer 132 and is located between the edge 1311a of the thermal insulation substrate 1311 and the inner wall 132a of the encapsulation cavity, that is, located in the region of the encapsulation layer 132 forming the aforementioned gap. The inner wall 32a of the encapsulation cavity herein refers to the inner wall of the encapsulation cavity directly opposite the side edge 1311a of the thermal insulation substrate 1311, that is, the third region directly opposite the side edge 1311a of the thermal insulation substrate 1311.

[0218] Furthermore, the two opposite surfaces of the thermal insulation substrate 1311 are bonded to the opposite inner walls of the encapsulation layer, that is, the two opposite surfaces of the thermal insulation substrate 1311 are bonded to the first area and the second area of the encapsulation layer 132 respectively. The side edge of the thermal insulation substrate 1311 is the edge connecting the two opposite surfaces of the thermal insulation substrate 1311. The thermal insulation substrate 1311 is square, and there is a gap between the side edges on all sides and the inner walls on all sides of the encapsulation cavity. In other words, the above-mentioned gap surrounds the four edges of the thermal insulation substrate 1311. Reserving this gap can, on the one hand, prevent the stress between the four edges of the thermal insulation substrate 1311 and the encapsulation layer from being too great to cause damage to the encapsulation layer 132, and on the other hand, reserve a certain volume change space for the phase change material therein.

[0219] Furthermore, the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is controlled to be 2-7 mm, preferably 2-5 mm, and more preferably 4-5 mm. When other conditions remain unchanged, the magnitude of the bag-breaking force is related to the distance between the weak portion and the edge of the thermal insulation substrate 1311.

[0220] Furthermore, the distance h2 between the weak portion 1312 and the inner wall 131a of the packaging cavity is greater than 3 mm, and can be 3 mm to 5 mm, to prevent the weak portion 1312 from being too close to the edge of the packaging layer and affecting the packaging strength of the packaging layer. Optionally, to enable the first packaging layer 131 to break and discharge gas more quickly in the event of thermal runaway, the distance h1 between the weak portion 1312 and the edge 1211a of the thermal insulation substrate 1211 is controlled to be 4 to 5 mm.

[0221] Furthermore, the weak portion 1322 is linear. Furthermore, the extension direction of the weak portion 1322 is the same as the extension direction of the edge 1311a of the thermal insulation substrate 1311. It is understood that in other examples, the weak portion 1322 may also be arc-shaped, etc., and is not limited thereto.

[0222] Furthermore, the total length of the weak portion 1322 accounts for 50% to 100% of the length of the edge of the thermal insulation substrate 1311, and can be 50% to 80%. For example, this length ratio can be 50%, 60%, 70%, 80%, 90%, or 100%. Controlling the total length ratio of the weak portion 1322 ensures that thermal runaway occurs and the package is broken promptly.

[0223] Furthermore, there are multiple weak portions 1322, which are spaced apart along the extending direction of the edge 1311a of the thermal insulation substrate 1311. The length of each weak portion 1322 is 1 / 20 to 1 / 10 of the edge 1311a of the thermal insulation substrate 1311, for example, 1 / 20, 1 / 15, or 1 / 10.

[0224] In a specific example, the weak portion 1322 is a notched area, and the length of the weak portion 1322 is 5-20 mm, and the width of the weak portion 1322 is 0.5-2 mm.

[0225] See also Figure 11 and Figure 12 Another embodiment of the present application further provides a battery 30, which includes any of the above-mentioned composite thermal insulation pads 10.

[0226] Furthermore, the battery 30 further includes a plurality of battery cells 20, and the composite thermal insulation pad 10 is disposed between at least two adjacent battery cells 20. Optionally, a composite thermal insulation pad 10 is disposed between any two adjacent battery cells 20.

[0227] It is understandable that the above-mentioned composite thermal insulation pad 10 may also be provided between the battery cell 20 and the inner wall of the battery 30 shell.

[0228] In some embodiments, the above-mentioned battery 30 also includes a third adhesive layer, one side of which is arranged on the outer surface of the outer insulation layer (the first insulation layer 11 and / or the second insulation layer 12) of the composite insulation pad 10, and the other side is used to bond the composite insulation pad 10 to a designated position of the battery 30, for example, the other side is bonded to a surface (for example, a larger surface) of the battery cell 20.

[0229] The battery 30 is provided with the above-mentioned composite thermal insulation pad 10, and its working principle is as follows: In the first stage, after a battery cell 20 in the battery 30 experiences thermal runaway, the heat is transferred to the adjacent (for example, adjacent) composite thermal insulation pad 10, and the phase change material layer 131 in the composite thermal insulation pad 10 absorbs the heat, thereby preventing the battery from thermal runaway. In the second stage, the phase change material layer 131 absorbs heat until a phase change occurs, absorbing a large amount of heat. In the third stage, the encapsulation layer 132 and the phase change material layer 131 fail: the phase change material in the phase change material layer 131 is converted into gas, bursting the encapsulation layer 132 and discharging the high-temperature gas. In the fourth stage, the first thermal insulation layer 11 and the second thermal insulation layer 12 and the optional thermal insulation substrate in the composite phase change layer 13 continue to play a role in thermal insulation.

[0230] The first and second stages are states before the composite thermal insulation pad 10 fails, and the third and fourth stages are states after the composite thermal insulation pad 10 fails. The third and fourth stages are not essential stages.

[0231] It is understood that the shape of the battery cell 20 includes but is not limited to square and cylindrical. The composite thermal insulation pad 10 can be arranged in a manner consistent with the shape of the battery cell 20.

[0232] In some embodiments, the battery cell 20 is square, and the composite thermal insulation pad 10 is disposed on the side surface (ie, the large surface) of the battery cell 20 to increase its contact area and improve the thermal insulation performance.

[0233] Furthermore, the composite thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0234] In this application, unless otherwise specified, "battery cell 20" refers to a basic unit capable of converting chemical energy into electrical energy. Furthermore, it generally includes at least a positive electrode, a negative electrode, and an electrolyte. During the battery's charge and discharge process, active ions are embedded in and released from the positive and negative electrodes. The electrolyte conducts active ions between the positive and negative electrodes.

[0235] It is understood that after multiple battery cells 20 are interconnected and arranged in a certain order, they can be directly housed in a housing to form a battery. Alternatively, multiple battery cells 20 can be first assembled into a battery module, and then the multiple battery modules are interconnected to form a whole, and finally the entire battery module is housed in a housing to form a battery.

[0236] For example, Figure 13 The battery cell 20 is a square structure as an example. The battery cell 20 includes a shell 21, a cover plate 23 and an electrode assembly 22. The electrode assembly 22 is accommodated in the shell 21. The shell 21 is provided with an opening, and the cover plate 23 is sealed in the opening. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the negative electrode sheet and the separator can be formed by a winding process or a lamination process. Furthermore, the electrode assembly 22 also includes an electrolyte, such as an electrolyte. The electrolyte is impregnated in the electrode assembly 22. The number of electrode assemblies 22 contained in the battery cell 20 can be one or more, and those skilled in the art can select according to specific actual needs.

[0237] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0238] Furthermore, the housing 21 is a rectangular parallelepiped housing, with the opening of the housing 21 extending in the height direction of the housing 21. Furthermore, the housing 21 has openings at both ends, with the two openings positioned opposite each other along the height direction of the housing 21. Furthermore, as a non-limiting example, the height of the housing 21 is 80 mm to 210 mm; further, as a non-limiting example, the length of the housing 21 is 90 mm to 240 mm; and further, as a non-limiting example, the width of the housing 21 is 20 mm to 80 mm.

[0239] Furthermore, the battery cell 20 and the shell 21 are rectangular shells, and the composite insulation pad 10 is arranged on the side of the battery cell 20 with a larger area. The side of the larger area is perpendicular to the above-mentioned width direction, that is, the side formed by the two sides of the above-mentioned length direction and height direction.

[0240] As a further non-limiting example, the wall thickness of the housing is 0.5 mm to 0.8 mm.

[0241] Furthermore, the housing 21 is an aluminum alloy housing; for example, a third-series aluminum alloy housing or a fifth-series aluminum alloy housing.

[0242] Furthermore, the aluminum alloy of the three-series aluminum alloy shell includes the following components in percentage by mass: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

[0243] Furthermore, the aluminum alloy of the fifth series aluminum alloy shell includes the following components in percentage by mass: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total components of other elements ≤ 0.15%.

[0244] Another embodiment of the present application further provides an electrical device, comprising the battery provided herein. The battery can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices, electric vehicles, electric trains, ships, satellites, energy storage systems, and the like. Examples of mobile devices include, but are not limited to, mobile phones and laptop computers; examples of electric vehicles include, but are not limited to, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, and electric trucks.

[0245] As an electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0246] Figure 14 The power consumption device 40 is used as an example. The power consumption device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the power consumption device's requirements for high power and high energy density of secondary batteries, a battery pack or battery module can be used.

[0247] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is generally required to be lightweight and thin, and may use a secondary battery as a power source.

[0248] The following are specific examples.

[0249] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0250] Example 1

[0251] The composite thermal insulation pad 10 of Example 1, such as Figure 2As shown, the composite phase change layer 13 includes a first thermal insulation layer 11, a first adhesive layer 151, a composite phase change layer 13, a second adhesive layer 152, and a second thermal insulation layer 12, which are stacked in sequence. The first thermal insulation layer 11 is connected to the encapsulation layer 132 via the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 via the second adhesive layer 152. The composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132. The encapsulation layer 132 is disposed on the outer surface of the phase change material layer 131 and forms an encapsulation cavity. The phase change material layer 131 is disposed within the encapsulation cavity.

[0252] The first heat-insulating layer 11 is a silica aerogel ceramic felt with a thickness of 1 mm;

[0253] The thickness of the first adhesive layer 151 is 0.05 mm and the material is silicone adhesive layer;

[0254] In the composite phase-change layer 13, the phase-change material layer 131 comprises a thermal insulation substrate and a phase-change material filling the pores of the thermal insulation substrate. The specific composition of the phase-change material is shown in Table 1 below; the total mass content of the phase-change material in the phase-change material layer 131 is 60%. The thermal insulation substrate is a silica nano-ceramic fiber felt, and the encapsulation layer 132 is an aluminum-plastic film with a thickness of 0.1 mm. The total thickness of the composite phase-change layer 13 is 1 mm.

[0255] The thickness of the second adhesive layer 152 is 0.05 mm and the material is silicone adhesive layer;

[0256] The second heat insulation layer 12 is a silica aerogel ceramic felt with a thickness of 1 mm.

[0257] Example 2

[0258] The structure and materials of Example 2 are essentially the same as those of Example 1, differing only in that the total thickness of the composite phase change layer 13 is 2 mm. Specifically, the thickness of the encapsulation layer 132 remains unchanged, while the thickness of the thermal insulation substrate is increased, resulting in a total thickness of the composite phase change layer 13 of 2 mm. All other parameters remain unchanged.

[0259] Examples 3 to 8

[0260] It is basically the same as Example 1, except that the composition and / or ratio of the phase change material are different, as shown in Table 1.

[0261] Table 1

[0262]

[0263] (1) The thermal insulation performance of the composite thermal insulation pads prepared in each embodiment was tested.

[0264] The test method is as follows: Heat the heating table to 600°C and maintain this temperature. Install temperature sensors on two opposite sides of the composite thermal insulation pad (a rectangle with a size of 100mm×100mm), place the composite thermal insulation pad on the heating table, and press the composite thermal insulation pad with an aluminum plate at a pressure of 3000N. By measuring the temperature of the two sides of the composite thermal insulation pad within 1200s, the thermal insulation effect of the composite thermal insulation pad can be determined. Among them, the side of the composite thermal insulation pad that is in direct contact with the heating table is the hot side, and the other side opposite to the hot side is the cold side. There are 3 temperature sampling points on each side, one is the center point, and the other two are distributed symmetrically with the center point, with a spacing of 15mm between them.

[0265] The test results of Example 1 and Example 2 are as follows: Figure 15 and Figure 16 Among them, there are three curves corresponding to the three sampling points of the hot surface and the cold surface, as shown in the figure, curves 1 to 3 are the hot surface, and curves 4 to 6 are the cold surface.

[0266] from Figure 15 As can be seen from the data, within the 1200-second test, when the hot side temperature reached nearly 600°C, the cold side temperature never exceeded 150°C due to the insulating effect of the composite thermal pad. Specifically, within the first 300 seconds, while the hot side temperature rose, the cold side maintained a lower temperature plateau (approximately 50°C). As the test time lengthened and heat dissipated further, the cold side temperature began to rise and then remained essentially at a plateau around 100°C. This plateau temperature is shown in Table 1.

[0267] from Figure 16 As can be seen from the graph, within the 1200-second test period, when the hot side temperature reaches nearly 600°C, the cold side temperature ideally remains below 140°C due to the insulating effect of the composite thermal pad. Specifically, within the first 600 seconds, while the hot side temperature rises, the cold side maintains a lower temperature plateau (approximately 50°C). As the test time increases and heat diffusion further develops, the cold side temperature rises and then remains essentially at a plateau around 100°C, representing the phase transition temperature.

[0268] As can be seen from Table 1, by adjusting the components and proportions of the phase change material, the phase change temperature of the phase change material layer can be adjusted to meet the requirements of different battery cells.

[0269] (2) Calculations of phase change heat absorption were performed on 0.05 kg of the composite thermal insulation mat produced in Example 2. Comparisons were made using the same weight of water. The results showed that the composite thermal insulation mat's heat absorption capacity was approximately 83% of that of the same mass of water. This means that 30% of the heat transferred to adjacent battery cells was absorbed by the composite thermal insulation mat. The composite thermal insulation mat's heat absorption capacity is roughly equivalent to that of water, which has a higher specific heat capacity, but is more battery-friendly than using water as a phase change material.

[0270] Examples 9 to 16

[0271] It is basically the same as Example 1, with the only difference being that the composite phase change layer 13 is different, specifically that the phase change material therein is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. The composition of the phase change material is the same as that of Example 1, with the main difference being that the wall material of the phase change microcapsules includes a polymer matrix and ceramic particles filled in the polymer matrix. The mass ratio of the polymer matrix to the ceramic particles, the mass ratio of the polymer matrix to the core material, and the Dv50 particle size parameters of the phase change microcapsules are shown in Table 2 below. Among them, the polymer matrix is a phenolic resin matrix, the ceramic particles are silica particles with a Dv50 of 0.5 μm, and the mass content of the phase change microcapsules in the phase change material layer is 60%.

[0272] The composite thermal insulation pads prepared in Examples 9 to 16 were subjected to a pressure resistance test, and the test method was as follows: a press was used to compress the composite thermal insulation pad at a compression rate of 2 mm / min. As the press was compressed, the greater the compression rate of the composite thermal insulation pad, the greater the stress on the composite thermal insulation pad. When the compression rate reached a certain value, the encapsulation layer in the composite thermal insulation pad broke, and the stress on the composite thermal insulation pad decreased rapidly. The inflection point where the stress decreased rapidly corresponded to the external pressure applied, which could reflect the pressure resistance of the composite thermal insulation pad. The test results are shown in Table 2.

[0273] Table 2

[0274]

[0275] Example 17

[0276] It is basically the same as Example 1, with the only difference being that the composition of the phase change material layer in the composite phase change layer is different; specifically, the phase change material layer 131 includes a thermal insulation substrate and a phase change material filled in the pores of the thermal insulation substrate, and the thermal insulation substrate is also silica nano-ceramic fiber felt. The main difference is that the phase change material is replaced by an equal mass of silica sol.

[0277] Example 18

[0278] This embodiment is essentially the same as Example 1, differing only in the composition of the phase change material in the composite phase change layer. Specifically, phase change material layer 131 includes a thermal insulation substrate and a phase change material filling the pores of the thermal insulation substrate. The thermal insulation substrate is also a silica nano-ceramic fiber felt. The main difference is that the phase change material is replaced with equal masses of crystalline hydrated salt (sodium carbonate decahydrate) and aluminum hydroxide sol. Furthermore, phase change material layer 131 also includes an infrared shielding agent filled in the pores of the thermal insulation substrate. The infrared shielding agent comprises titanium dioxide and silicon oxide.

[0279] The following is a compression performance test.

[0280] The single composite phase change layer in Example 1 was used as a sample (sample area was 100 mm*100 mm), and a stress-strain test was performed to obtain a compressive stress-strain curve, as shown in FIG. Figure 17 As shown, the average strain of the sample under stress of 0.5-5 MPa, and further 0.5-4 MPa, ranges from 8% to 20%, and further from approximately 10% to 16%. The package failure rupture pressure of the package thermal conductive layer is slightly greater than 4 MPa.

[0281] The first thermal insulation layer (silica aerogel ceramic felt) in Example 1 was used as a sample (sample area was 100 mm*100 mm), and a stress-strain test was performed to obtain a compression stress-strain curve, as shown in FIG. Figure 18 As shown, the strain of the sample is 25% to 70% when the stress is 0.5 to 5 MPa, the strain of the sample is 25% to 70% when the stress is 0.5 to 3 MPa, and the strain of the sample is 29% to 57% when the stress is 0.5 to 2.8 MPa.

[0282] The composite thermal insulation pad in Example 1 was used as a sample (sample area was 100 mm*100 mm), and multiple groups of parallel stress-strain tests were performed to obtain a compression stress-strain curve, as shown in FIG. Figure 19 As shown, the strain of the composite thermal insulation pad as a whole is 15% to 35% when subjected to a stress of 0.5 to 4 MPa, and further 15% to 35% when subjected to a stress of 0.5 to 3 MPa, and further 15% to 30%.

[0283] The following is a component test of the phase change material layer in the composite phase change layer of the composite thermal insulation pad of Example 18. Specifically, an electron scanning electron microscope and energy spectrum combined analysis (SEM&EDS) were used to obtain SEM images and EDS images, as shown in FIG. Figure 20 and Figure 21 The atomic percentage of each element is shown in Table 3:

[0284] Table 3

[0285]

[0286] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0287] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A composite thermal insulation pad, characterized in that: include: A composite phase change layer includes a phase change material layer and an encapsulation layer, wherein the encapsulation layer is arranged on the outer peripheral side of the phase change material layer, the phase change material layer includes a thermal insulation substrate and a phase change material, and at least part of the phase change material is filled in the thermal insulation substrate; wherein the strain of the composite phase change layer when subjected to a stress of 0.5~5MPa is 8%~20%.

2. The composite thermal insulation pad according to claim 1, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The phase change material includes at least one of crystalline water and salt, phase change molten salt, paraffin, silicone oil, silica sol, aluminum sol, silica-alumina sol, fatty acid and alcohol; (2) The thermal insulation substrate includes nano-ceramic fibers, and the nano-ceramic fibers include at least one of silica fibers, alumina fibers, zirconia fibers, alumina-silicon ceramic fibers, borosilicate ceramic fibers, boron-aluminum ceramic fibers, and zirconium-aluminum-silicon ceramic fibers; (3) The thermal insulation substrate comprises nano-ceramic fibers, and the average diameter of the nano-ceramic fibers is 200-800 nm, and the thickness of the thermal insulation substrate is 1 mm-2 mm; (4) In the phase change material layer, the mass ratio of the thermal insulation substrate to the phase change material is 1:(0.8-3); (5) The phase change material layer further includes at least one of an infrared shielding agent, a flame retardant, and a thermal conductor; wherein the infrared shielding agent includes at least one of titanium dioxide, silicon oxide, and carbon powder; the flame retardant includes one or more of ammonium dihydrogen phosphate, tris(2,3-dibromopropyl) phosphate, thiophosphate triisocyanate, urea, ammonium pentaborate, ammonium bicarbonate, or melamine cyanurate; and the thermal conductivity of the thermal conductor is greater than 20 W / (mK); (6) At least part of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; wherein the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material; (7) A weak portion is provided on the area where the packaging layer forms the packaging cavity.

3. The composite thermal insulation pad according to claim 2, characterized in that: At least a portion of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; wherein the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material; and the composite thermal insulation pad meets at least one of the following conditions: (1) The wall material includes a polymer matrix, and the mass ratio of the polymer matrix to the core material is 1:(1.3-3); (2) The Dv50 particle size of the phase change microcapsules is 0.5~8μm; (3) The thermal conductivity of the wall material at 25°C is ≥ 0.32 W / mK; (4) The melting point of the wall material is greater than 98°C; (5) In the phase change material layer, the mass content of the phase change microcapsules is 50% to 70%.

4. The composite thermal insulation pad according to claim 3, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The mass ratio of the polymer matrix to the core material is 1:(1.3-1.6); (2) The wall material further comprises ceramic particles filled in the polymer matrix, and the mass ratio of the polymer matrix to the ceramic particles is 3:(4-11); (3) The Dv50 particle size of the phase change microcapsules is 0.5~8μm.

5. The composite thermal insulation pad according to claim 4, characterized in that: The mass ratio of the polymer matrix to the ceramic particles is 3:(7-11).

6. The composite thermal insulation pad according to claim 1, characterized in that: The phase change material includes a first paraffin wax having a melting point of 100-110° C. and a second paraffin wax having a melting point of 110-120° C.

7. The composite thermal insulation pad according to claim 6, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The mass ratio of the first paraffin wax to the second paraffin wax is 33:(37-53); (2) The molecular formula of the first paraffin is C m H 2m+2 , where 38≤m≤43; (3) The molecular formula of the second paraffin is C w H 2w+2 , where 57≤w≤64.

8. The composite thermal insulation pad according to claim 6, characterized in that: The phase change material further includes a third paraffin wax having a melting point of 63-72°C.

9. The composite thermal insulation pad according to claim 8, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The mass ratio of the third paraffin wax, the first paraffin wax and the second paraffin wax is (20-25): (34-57): (60-63); (2) The molecular formula of the third paraffin is C n H 2n+2 , where 28≤n≤33.

10. The composite thermal insulation pad according to any one of claims 1 to 9, characterized in that: The composite thermal insulation pad further includes an outer thermal insulation layer provided on at least one side of the outer periphery of the packaging layer.

11. The composite thermal insulation pad according to claim 10, characterized in that: The outer heat insulation layer has a strain of 25% to 70% when subjected to a stress of 0.5 to 5 MPa.

12. The composite thermal insulation pad according to claim 10, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The outer insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K; (2) The density of the outer insulation layer is 0.2~0.22g / cm 3 ; (3) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating; (4) The composite thermal insulation pad further includes a strain detection component, which is disposed within the outer thermal insulation layer or on the outer surface of the outer thermal insulation layer; (5) The composite thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the encapsulation layer are connected via the adhesive layer; (6) The composite thermal insulation pad further comprises a release adhesive layer, wherein the release adhesive layer comprises an adhesive layer and a release film, wherein the adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

13. The composite thermal insulation pad according to claim 10, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The outer thermal insulation layer is a ceramic material layer; (2) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film; (3) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm; (4) The thickness of the composite phase change layer is 1 mm to 6 mm; (5) The thickness of the outer insulation layer is 0.5 mm to 8 mm; (6) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer; (7) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is 0.15-12:1; (8) The outer heat insulation layer is provided on at least one of the two sides in the thickness direction of the composite phase change layer; (9) The length and width of the outer heat-insulating layer are respectively adapted to the length and width of the composite phase change layer; or, at least one of the length and width of the outer heat-insulating layer is larger than the corresponding length or width of the composite phase change layer.

14. The composite thermal insulation pad according to claim 10, characterized in that: The outer heat insulation layer includes a first heat insulation layer and a second heat insulation layer; The first thermal insulation layer and the second thermal insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first thermal insulation layer and the second thermal insulation layer; The composite thermal insulation pad has a strain of 15% to 35% when subjected to a stress of 0.5 to 4 MPa.

15. The composite thermal insulation pad according to claim 14, characterized in that: The edges of the first heat-insulating layer and the second heat-insulating layer are connected to each other to form an assembly cavity, and the composite phase change layer is located in the assembly cavity.

16. The composite thermal insulation pad according to claim 15, characterized in that: An edge of at least one side surface of at least one of the first heat-insulating layer and the second heat-insulating layer forms a convex portion, and the convex portion encloses and forms at least a portion of the assembly cavity.

17. The composite thermal insulation pad according to claim 15, characterized in that: The packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

18. The composite thermal insulation pad according to claim 14, characterized in that: The composite thermal insulation pad also includes a first packaging frame and a second packaging frame. The first packaging frame is arranged on one side of the first thermal insulation layer, and the second packaging frame is arranged on one side of the second thermal insulation layer. The first packaging frame and the second packaging frame cooperate to fix the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer.

19. The composite thermal insulation pad according to claim 17, characterized in that: The packaging layer has a packaging margin portion, and the packaging margin portion is located between the first packaging frame and the second packaging frame.

20. The composite thermal insulation pad according to claim 17, characterized in that: The first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in a limiting space formed by the first limiting groove and the second limiting groove.

21. The composite thermal insulation pad according to claim 17, characterized in that: The outer surface of the first heat insulation layer is flush with the outer surface of the first packaging frame, and / or the outer surface of the second heat insulation layer is flush with the outer surface of the second packaging frame.

22. The composite thermal insulation pad according to claim 13, characterized in that: The composite thermal insulation pad also includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

23. A battery, characterized in that: Comprising the composite thermal insulation pad according to any one of claims 1 to 22.

24. The battery according to claim 23, characterized in that It also includes a plurality of battery cells, and the composite thermal insulation pad is arranged between at least two adjacent battery cells.

25. The battery according to claim 24, characterized in that The composite thermal insulation pad is arranged between the large surfaces of two adjacent battery cells.

26. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 23 to 25.

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