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 heat insulation pad body; and the heat conduction layer is arranged in the heat insulation pad body. According to the composite heat insulation pad, on one hand, the heat insulation pad body can play a role in heat insulation, on the other hand, the heat conduction layer is arranged in the heat insulation pad body, if heat is conducted into the heat insulation pad body and reaches the heat conduction layer, the heat conduction layer can rapidly and uniformly disperse the heat to the periphery, and then the effect of rapid heat dissipation is achieved. The composite heat insulation pad is applied to the battery, when the battery is in a normal working state, the heat insulation pad body mainly plays a role in heat insulation, and when the battery is abnormal in heating, the heat conduction layer can play a role in rapid diffusion, so that the composite heat insulation pad has a role in retarding 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 rapid development of new energy technologies, batteries are being used more and more widely in many fields, and people are placing higher and higher demands on battery performance, such as the energy density of batteries.

[0003] However, battery cells with higher energy density have high residual energy after thermal runaway. When one cell experiences thermal runaway, the heat from it continuously transfers to adjacent cells, causing heat diffusion throughout the battery and causing serious damage. Therefore, how to mitigate battery thermal runaway is an urgent problem that needs to be solved. Summary of the Invention

[0004] Based on this, it is necessary to provide a composite thermal insulation pad, battery and electrical device to prevent the problem of battery thermal runaway.

[0005] In a first aspect, the present application provides a composite thermal insulation pad, comprising:

[0006] the thermal insulation pad body; and

[0007] The heat-conducting layer is arranged inside the heat-insulating pad body.

[0008] The composite thermal insulation pad described in this application not only provides insulation through the pad body, but also incorporates a heat-conducting layer within the pad body. When heat is conducted into the pad body and reaches the heat-conducting layer, the layer quickly and evenly disperses the heat to the surrounding area, thereby rapidly dissipating the heat. When applied to a battery, the pad body primarily provides insulation during normal battery operation. When the battery overheats abnormally, the heat-conducting layer rapidly diffuses the heat, thereby preventing thermal runaway.

[0009] In some embodiments, the heat conductive layer includes one or a stack of at least two of a phase change material layer, a metal layer, and a graphene film layer.

[0010] In some embodiments, the heat conductive layer includes at least two stacked phase change material layers, and an intermediate layer is provided between at least two of the phase change material layers, and the intermediate layer includes a stack of one or both of a metal layer and a graphene film layer.

[0011] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0012] (1) The ratio of the thickness of the intermediate layer to the total thickness of the phase change material layer is (0.3-5):100;

[0013] (2) The thickness of the intermediate layer is 0.02 mm to 0.04 mm;

[0014] (3) The projection area of the intermediate layer on the phase change material layer accounts for 90% to 100% of the area of the phase change material layer.

[0015] In some embodiments, the phase change material layer includes a heat insulation substrate and a phase change material, and at least a portion of the phase change material is filled in the heat insulation substrate.

[0016] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0017] (1) The phase change material includes at least one of crystalline hydrated salt, phase change molten salt, paraffin, silicone oil, silica sol, aluminum sol, silica-alumina sol, fatty acid and alcohol;

[0018] (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;

[0019] (3) The thermal insulation substrate comprises nano-ceramic fibers, and the average diameter of the nano-ceramic fibers is 200 to 800 nm, and the thickness of the thermal insulation substrate is 1 mm to 2 mm;

[0020] (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); optionally, the thermal insulation substrate is a ceramic thermal insulation substrate;

[0021] (5) 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; optionally, the wall material includes a polymer matrix, and the mass ratio of the polymer matrix to the core material is 1:(1.3~3); optionally, the Dv50 particle size of the phase change microcapsules is 0.5~8μm.

[0022] In some embodiments, the thermal insulation pad body is provided with a hollow cavity, and the heat conductive layer is provided in the hollow cavity;

[0023] Optionally, the heat-conducting layer includes a solid phase-change material layer.

[0024] In some embodiments, the composite thermal insulation pad further comprises:

[0025] The packaging layer is provided on the outer peripheral side of at least one of the heat-conducting layer and the thermal insulation pad body.

[0026] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0027] (1) The encapsulation layer includes a first encapsulation layer, which is provided on the outer periphery of the heat-conducting layer and separately encapsulates the heat-conducting layer, and the first encapsulation layer and the heat-conducting layer constitute an encapsulated heat-conducting layer; optionally, the strain of the encapsulated heat-conducting layer when subjected to a stress of 0.5 to 5 MPa is 8% to 20%;

[0028] (2) The packaging layer further includes a second packaging layer, which is provided on the outer peripheral side of the thermal insulation pad body and separately packages the thermal insulation pad body;

[0029] (3) The packaging layer further includes a third packaging layer, which is provided on the common outer peripheral side of the thermal insulation pad body and the thermal conductive layer, and packages the thermal insulation pad body and the thermal conductive layer together.

[0030] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0031] (1) The first encapsulation layer, the second encapsulation layer, and the third encapsulation layer are each independently an aluminum-plastic film or a polymer encapsulation film;

[0032] (2) The thickness of the first encapsulation layer is 0.1 mm to 0.3 mm;

[0033] (3) The first packaging layer has a first packaging margin portion, and the first packaging margin portion is folded and arranged inside the thermal insulation pad body;

[0034] (4) The thickness of the second encapsulation layer and the third encapsulation layer are each independently 0.05 mm to 0.1 mm;

[0035] (5) The thickness of the thermal conductive layer accounts for 70% to 96% of the total thickness of the package thermal conductive layer;

[0036] (6) A weak portion is provided on the area of the first packaging layer constituting the packaging cavity; optionally, the heat-conducting layer includes a phase change material layer; optionally, the weak portion is an area with a relatively thin thickness and / or relatively weak material strength;

[0037] (7) The composite thermal insulation pad also includes a strain detection component, which is arranged on the thermal insulation pad body; optionally, the strain detection component is arranged inside the thermal insulation pad body, or on the outer surface of the thermal insulation pad body.

[0038] In some embodiments, the thermal insulation pad body includes a first thermal insulation layer and a second thermal insulation layer located on both sides of the thermal conductive layer in a thickness direction;

[0039] Optionally, the strain of the first thermal insulation layer and the second thermal insulation layer when subjected to a stress of 0.5 to 5 MPa is 25% to 70%;

[0040] Optionally, the strain of the composite thermal insulation pad is 15% to 35% when subjected to a stress of 0.5 to 4 MPa.

[0041] In some embodiments, the encapsulation layer includes a second encapsulation layer, and the second encapsulation layer is provided on the outer peripheral side of the first thermal insulation layer and / or the outer peripheral side of the second thermal insulation layer;

[0042] And / or, the encapsulation layer includes a third encapsulation layer, and the third encapsulation layer is provided on a common outer peripheral side of the first heat-insulating layer, the heat-conducting layer, and the second heat-insulating layer.

[0043] In some embodiments, the second encapsulation layer has a second encapsulation margin portion, and the second encapsulation margin portion is folded and located between the thermal conductive layer and at least one of the first thermal insulation layer and the second thermal insulation layer.

[0044] In some embodiments, edges of the first thermal insulation layer and the second thermal insulation layer cooperate with each other to form an assembly cavity, and the heat conductive layer is located in the assembly cavity.

[0045] In some embodiments, 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 at least a portion of the assembly cavity.

[0046] In some embodiments, the composite thermal insulation pad further includes a first packaging frame and a second packaging frame, and the first packaging frame and the second packaging frame cooperate to fix the thermal insulation pad body and the heat conductive layer.

[0047] In some embodiments, the first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the thermal insulation pad body and the thermal conductive layer are limited in the limiting space formed by the first limiting groove and the second limiting groove.

[0048] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0049] (1) The thermal insulation pad body is a ceramic material layer;

[0050] (2) The thickness of the heat-conducting layer is 1 mm to 6 mm;

[0051] (3) The thickness of the thermal insulation pad body is 0.5mm to 8mm;

[0052] (4) The ratio of the thickness of the thermal conductive layer to the thickness of the thermal insulation pad body is 0.15 to 12:1;

[0053] (5) The length and width of the thermal insulation pad body are respectively adapted to the length and width of the thermal conductive layer; or at least one of the length and width of the thermal insulation pad body is larger than the corresponding length or width of the thermal conductive layer;

[0054] (6) The composite thermal insulation pad also includes a release adhesive layer, which includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the thermal insulation pad body, and the release film is arranged on the outer surface of the adhesive layer.

[0055] In a second aspect, the present application provides a battery comprising the above-mentioned composite thermal insulation pad.

[0056] 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.

[0057] In some embodiments, the composite thermal insulation pad is disposed between the large surfaces of at least two adjacent battery cells.

[0058] In a third aspect, the present application provides an electrical device comprising the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] 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;

[0060] Figure 2 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0061] Figure 3 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0062] Figure 4 for Figure 2 A schematic diagram of the front structure of the packaged heat-conducting layer of the composite thermal insulation pad shown;

[0063] Figure 5 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0064] Figure 6 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0065] Figure 7This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0066] Figure 8 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0067] Figure 9 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0068] Figure 10 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0069] Figure 11 This is a schematic diagram of the three-dimensional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0070] Figure 12 for Figure 11 A schematic cross-sectional view of the composite thermal insulation pad shown in FIG.

[0071] Figure 13 This is a schematic cross-sectional structure diagram of a composite thermal insulation pad according to another embodiment of the present application;

[0072] Figure 14 This is a schematic structural diagram of a battery according to one embodiment of the present application;

[0073] Figure 15 This is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0074] Figure 16 is a schematic structural diagram of a battery cell in a battery according to one embodiment;

[0075] Figure 17 A schematic diagram of an electrical device using a battery as a power source according to one embodiment of the present application;

[0076] Figure 18 The thermal insulation performance curves of the composite thermal insulation pads prepared in Example 1 and Example 2 are shown;

[0077] Figure 19 is a compressive stress-strain curve of a sample with a separate package heat-conducting layer in Example 1;

[0078] Figure 20 is a compressive stress-strain curve of the sample with the first thermal insulation layer alone in Example 1;

[0079] Figure 21 The compressive stress-strain curve of the composite thermal insulation pad in Example 1 is taken as a sample;

[0080] Figure 22 is an SEM image of the phase change material layer encapsulated in the heat conductive layer of the composite thermal insulation pad of Example 4;

[0081] Figure 23 This is an EDS image of the phase change material layer in the encapsulated heat conductive layer in the composite thermal insulation pad of Example 4.

[0082] Description of reference numerals:

[0083] 10. Composite thermal insulation pad; 11. Thermal insulation pad body; 111. First thermal insulation layer; 112. Second thermal insulation layer; 12. Thermal conductive layer; 121. Phase change material layer; 1211. Thermal insulation substrate; 1211a. One side edge of the thermal insulation substrate; 122. Intermediate layer; 131. First packaging layer; 131a. Inner wall of the packaging cavity; 1311. First packaging margin; 1312. Weak portion; 132. Second packaging layer; 1321. Second packaging margin; 133. Third packaging layer; 141. First packaging frame; 142. Second packaging frame; 151. First adhesive layer; 152. Second adhesive layer; 17. Strain detection element; 172. External wires;

[0084] 20. Battery cell; 21. Housing; 22. Electrode assembly; 23. Cover plate;

[0085] 30. Battery;

[0086] 40. Electrical equipment. DETAILED DESCRIPTION

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] In order to solve the above-mentioned battery thermal runaway problem and reduce the damage and risk to the entire battery.

[0097] See also Figure 1 In one embodiment of the present application, a composite thermal insulation pad 10 is provided, comprising a thermal insulation pad body 11 and a heat-conducting layer 12 . The heat-conducting layer 12 is disposed within the thermal insulation pad body 11 .

[0098] It is understood that the heat-conducting layer 12 is provided inside the heat-insulating pad body 11, including but not limited to the following forms: the heat-conducting layer 12 is completely surrounded by the heat-insulating pad body 11 (see Figure 1 (a)), for example, the heat-conducting layer 12 is completely embedded in the heat-insulating pad body 11; the heat-conducting layer 12 is partially surrounded by the heat-insulating pad body 11 but the heat-conducting layer 12 is located inside the heat-insulating pad body 11 (see Figure 1 In (b), for example, the heat-conducting layer 12 may be located between the two heat-insulating layers, and the heat-conducting layer 12 does not protrude from the heat-insulating layers. The two heat-insulating layers here constitute the heat-insulating pad body 11 .

[0099] The composite thermal insulation pad 10 described above in this application has a thermal insulation function, in which the thermal insulation pad body 11 can function as a heat insulator. Furthermore, a heat-conducting layer 12 is disposed within the thermal insulation pad body 11. When heat is conducted to the interior of the thermal insulation pad body 11 and reaches the heat-conducting layer 12, the heat-conducting layer 12 can quickly and evenly disperse the heat to the surrounding area, thereby rapidly dissipating heat. This composite thermal insulation pad is applied to batteries. When the battery is operating normally, the thermal insulation pad body 11 primarily functions as a heat insulator. When the battery generates abnormal heat, the heat-conducting layer 12 can rapidly diffuse the heat, thereby preventing thermal runaway.

[0100] In some embodiments, the thermal conductive layer 12 includes a phase change material layer 121, a metal layer, and a graphene film layer, or a stack of at least two of them. When heat is conducted to the thermal conductive layer 12, the phase change material layer 121 receives the heat and transfers it inward, i.e., it is absorbed by the phase change material layer 121, thereby rapidly dissipating heat. The metal layer and the graphene film layer, as good conductors of heat, can quickly and evenly disperse the heat to the surroundings, thereby rapidly dissipating heat. In addition, the metal layer also has a good effect of suppressing thermal radiation, which can further enhance the thermal insulation effect of the composite thermal insulation pad.

[0101] For example, the thermal conductive layer 12 may include any one of a phase change material layer 121, a metal layer and a graphene film layer, or may include a stack of any one of a metal layer and a graphene film layer and a phase change material layer 121, or may include a stack of a metal layer and a graphene film layer, or may include a stack of three layers: a phase change material layer 121, a metal layer and a graphene film layer.

[0102] See also Figure 2 In some embodiments, the heat conducting layer 12 includes at least two stacked phase change material layers 121 and an intermediate layer 122 disposed between at least two phase change material layers 121. The intermediate layer 122 includes a stack of one or both of a metal layer and a graphene film layer.

[0103] It is understood that the number of phase change material layers 121 in the heat conducting layer 12 may be greater than 2. Furthermore, an intermediate layer 122 is provided between every two adjacent phase change material layers 121 .

[0104] Furthermore, when the intermediate layer 122 includes a stack of a metal layer and a graphene film layer, the metal layer may be in contact with the phase change material layer 121, the graphene film layer may be in contact with the phase change material layer 121, or the metal layer may be in contact with one phase change material layer 121 and the graphene film layer may be in contact with another phase change material layer 121.

[0105] Furthermore, the metal layer includes a pure metal layer or an alloy layer of at least one of copper, aluminum, and iron. As an example, the metal layer is a copper metal layer or an aluminum metal layer. Among them, the copper metal layer has a better effect of suppressing thermal radiation.

[0106] In this way, the above-mentioned intermediate body is set between the two layers of phase change material 121. When one side of the composite thermal insulation pad is in contact with or close to the heat source, the thermal insulation pad body 11 first plays a heat insulation role. When the heat is transferred to the phase change material layer 121 on this side, the phase change material layer 121 absorbs heat and undergoes a phase change, which plays a role in cooling the overall temperature of the composite thermal insulation pad and also plays a role in slowing down its further diffusion. When the heat is further transferred to the intermediate layer 122, the intermediate layer 122 can quickly diffuse the heat along its surface. On the one hand, due to the heat conduction effect of the intermediate layer 122, it can trigger the phase change material layer 121 on the other side of the intermediate layer 122 to undergo a phase change over a larger area and absorb heat and cool down. On the other hand, it can also diffuse the heat to the surrounding area, further improving the thermal insulation effect of the composite thermal insulation pad.

[0107] In some embodiments, the ratio of the thickness of the intermediate layer 122 to the total thickness of the phase-change material layer 121 is (0.3-5):100. Generally, the thickness of the intermediate layer 122 is relatively thin, and the thickness of the phase-change material layer 121 is relatively large. As an example, the ratio of the thickness of the intermediate layer 122 to the thickness of the phase-change material layer 121 can be 0.3:100, 0.5:100, 0.8:100, 1:100, 2:100, 3:100, 4:100, or 5:100. In some examples, the thickness ratio can be a range consisting of any two of the above-mentioned points. The following is similar.

[0108] In some embodiments, the thickness of the intermediate layer 122 is 0.02 mm to 0.04 mm. As an example, the thickness of the intermediate layer 122 may be 0.02 mm, 0.03 mm, or 0.04 mm. For example, the intermediate layer 122 is a metal layer.

[0109] 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. During testing, 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 of these five locations serving as the test value.

[0110] In some embodiments, the projected area of the intermediate layer 122 on the phase-change material layer 121 accounts for 90% to 100% of the area of the phase-change material layer 121. It should be understood that the projected area of the intermediate layer 122 on the phase-change material layer 121 refers to the projected area perpendicular to the thickness direction. In this way, the projected area of the intermediate layer 122 on the phase-change material layer 121 is equal to or smaller than the area of the phase-change material layer 121, allowing the intermediate layer 122 to be covered by the phase-change material layer 121, fully utilizing the heat transfer function of the intermediate layer 122 and triggering phase change heat absorption over a larger area of the phase-change material layer 121.

[0111] In some embodiments, the phase change material includes a first paraffin wax having a melting point of 100-110°C.

[0112] In some embodiments, the phase change material further includes a second paraffin wax having a melting point of 110-120°C.

[0113] 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 a specific mass ratio, the phase change temperature of the phase change material layer 121 can be controlled to be around 105°C to 110°C, which is 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.

[0114] Furthermore, the molecular formula of the first paraffin is C m H 2m+2 , where 38≤m≤43.

[0115] Furthermore, the molecular formula of the second paraffin is C w H 2w+2 , where 57≤w≤64.

[0116] In some embodiments, the phase change material further includes a third paraffin wax having a melting point of 63-72°C.

[0117] 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). In this way, by combining the three paraffin waxes in a specific mass ratio, the phase change temperature of the phase change material layer 121 can be controlled at about 100°C, which is particularly suitable for batteries with a self-heating temperature of about 110°C, such as NCM batteries. The temperature of NCM batteries rises rapidly after thermal runaway, so the phase change temperature of the phase change material layer 121 is controlled at about 100°C. When the first battery cell thermally runs away, due to the presence of different proportions of paraffin components in the phase change material layer 121, gradient melting will occur, which can control the cold surface temperature of the composite thermal insulation pad below 100°C, and keep the large surface temperature of the adjacent battery cell in thermal runaway below 100°C. The adjacent battery cell will not undergo self-heating reaction, so the composite thermal insulation pad can effectively prevent thermal runaway.

[0118] Furthermore, the molecular formula of the third paraffin is C n H 2n+2 , where 28≤n≤33.

[0119] In some embodiments, the thermal insulation pad body 11 is provided with a hollow cavity, and the heat conductive layer 12 is provided in the hollow cavity.

[0120] In one specific example, the thermally conductive layer 12 includes a solid phase-change material layer 121, which is disposed within the hollow cavity. Because the phase-change material layer 121 is solid and disposed within the hollow cavity, it does not require encapsulation at room temperature. Under normal conditions, the solid phase-change material layer 121 does not affect the thermal insulation performance of the thermal pad body 11. However, the phase-change material within the hollow cavity of the thermal pad body 11 can absorb heat to a certain extent.

[0121] It is understandable that the heat-conducting layer 12 and the heat-insulating pad body 11 may also be encapsulated to protect the heat-conducting layer 12 and the heat-insulating pad body 11 , or to physically isolate the two.

[0122] In some embodiments, the composite thermal insulation pad further includes a packaging layer, which is disposed on the outer periphery of at least one of the heat-conducting layer 12 and the thermal insulation pad body 11 .

[0123] It can be understood that the outer peripheral sides of the thermally conductive layer 12 and the thermally insulating pad body 11 are all the outer peripheral surfaces of the thermally conductive layer 12 and the thermally insulating pad body 11 as an independent whole. The outer peripheral sides of the thermally conductive layer 12 and the thermally insulating pad body 11 are all the outer peripheral surfaces of the thermally conductive layer 12 and the thermally insulating pad body 11 as a whole formed by the thermally conductive layer 12 and the thermally insulating pad body 11.

[0124] It is understandable that the encapsulation layer can be provided on the outer peripheral side of either the heat-conducting layer 12 or the heat-insulating pad body 11 , or on the outer peripheral side formed by the two together, or a combination of these.

[0125] See also Figure 3 In some embodiments, the encapsulation layer includes a first encapsulation layer 131. The first encapsulation layer 131 is arranged on the outer peripheral side of the thermally conductive layer 12, constituting an encapsulated thermally conductive layer. The encapsulated thermally conductive layer is arranged inside the thermal insulation pad body 11. In this way, the first encapsulation layer 131 physically isolates the thermally conductive layer 12 from the thermal insulation pad body 11, and the thermally conductive layer 12 does not affect the thermal insulation performance of the thermal insulation pad body 11. It can be understood that the first encapsulation layer 131 encapsulates the thermally conductive layer 12 separately, and does not encapsulate the thermal insulation pad body 11.

[0126] In this specific example, since the thermally conductive layer 12 includes a first encapsulation layer 131, the thermally conductive layer 12 may include a solid, liquid, or semi-solid phase change material layer 121. Before the first encapsulation layer 131 fails, the phase change material will not diffuse into the interior of the thermal insulation pad body 11, thereby forming a heat conduction path and thus not changing the structure and thermal insulation performance of the thermal insulation pad body 11. Of course, the thermally conductive layer 12 may also include the aforementioned intermediate layer 122.

[0127] Optionally, the material of the phase change material layer 121 includes, but is not limited to, crystalline hydrated salts, phase change molten salts, paraffin, silicone oil, silica sol, aluminum sol, silica-aluminum sol, fatty acids, alcohols, and other substances that can undergo phase change and absorb heat, which have a wider range of applications and can therefore provide better thermal insulation performance. Furthermore, the crystalline hydrated salt includes, but is not limited to, at least one of sodium carbonate and calcium chloride, such as at least one of sodium carbonate decahydrate (Na2CO3·10H2O) and calcium chloride hexahydrate (CaCl2·6H2O). Aluminum sol includes aluminum hydroxide sol.

[0128] In addition, because the phase change material of the phase change material layer 121 will undergo phase change, for example, the solid phase change material at room temperature will turn into liquid after absorbing heat, the first packaging layer 131 can also play the role of isolating the phase change material that is liquid after phase change from the thermal insulation pad body 11.

[0129] In addition, some preparation processes inevitably cause the phase change material to contain moisture. The structure in which the phase change material layer 121 is disposed in the packaging cavity of the first packaging layer 131 can prevent moisture overflow from causing adverse effects on the battery.

[0130] In some examples, the encapsulation layer may be formed by encapsulating two encapsulation films, for example, by encapsulating by edge pressing or edge wrapping, so that an encapsulation margin is provided at the edge of each encapsulation layer.

[0131] In some embodiments, the first packaging layer 131 has a first packaging margin (see Figure 7 ). Furthermore, the first package margin portion is formed into a pressed edge structure by pressing the edge.

[0132] See also Figure 3Furthermore, the first packaging margin can also be folded and positioned between the thermally conductive layer 12 and the thermal insulation pad body 11. This creates a wraparound structure around each edge of the packaging film, which, compared to the previously mentioned pressed edge structure, maximizes the area of the first packaging layer 131. In other words, if the same size packaging film is used with the wraparound structure, a larger area of the thermally conductive layer 12 can be filled within the packaging film, thereby increasing the contact area between the composite thermal insulation pad 10 and the larger surface of the battery, thereby improving thermal insulation performance.

[0133] In some embodiments, the first packaging layer 131 is an aluminum-plastic film or a polymer packaging film.

[0134] Furthermore, the first encapsulation layer 131 is an aluminum-plastic film. Specifically, the first encapsulation layer 131 includes a polypropylene layer, an aluminum layer, and a nylon layer stacked from the inside to the outside.

[0135] Furthermore, the polymer packaging film may be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0136] In some embodiments, the thickness of the first encapsulation layer 131 is 0.1 mm to 0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and optionally 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0137] See also Figure 4 In some embodiments, the thermally conductive layer 12 includes a phase-change material layer 121, and a weak portion is defined in the region of the first encapsulation layer 131 that forms the encapsulation cavity. Because the weak portion is located in a vulnerable area, when the phase-change material layer 121 in the thermally conductive layer 12 absorbs a large amount of heat, the phase-change material in the phase-change material layer 121 undergoes a phase change, causing the first encapsulation layer 131 to bulge. This allows the first encapsulation layer 131 to rupture promptly at the weak portion in the event of thermal runaway, further reducing the damage to the battery as a whole.

[0138] It can be understood that the weak portion 1312 on the first encapsulation layer 131 is a relatively weak area on the first encapsulation layer 131 .

[0139] In some embodiments, the weak portion 1312 is a region of relatively thin thickness and / or relatively weak material strength. In other words, the weak portion 1312 can be a region of relatively thin thickness but constant material strength, which can be formed by locally thinning the first encapsulation layer 131. The weak portion 1312 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 first encapsulation layer 131, for example, by using materials of different strengths. Alternatively, the weak portion 1312 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.

[0140] Furthermore, the weak portion 1312 is a notch region formed on the first encapsulation layer 131. It can be understood that the notch region is formed by thinning the surface of the first encapsulation layer 131 by embossing, and the thickness of the notch region is relatively thin.

[0141] Furthermore, the weak portion 1312 can be disposed on the outside or inside of the first encapsulation layer 131 . The outside refers to the surface of the first encapsulation layer 131 away from the phase change material layer 121 , and the inside refers to the surface of the first encapsulation layer 131 close to the phase change material layer 121 .

[0142] Furthermore, the depth of the weak portion 1312 accounts for 15% to 50% of the thickness of the first packaging layer 131, for example, 15%, 20%, 30%, 35%, 40%, 45%, or 50%. Controlling this thickness ratio allows the packaging layer to provide both good isolation when no package breakage is required and good timely package breakage in the event of thermal runaway.

[0143] Furthermore, the aluminum-plastic film includes an aluminum foil layer and plastic film layers arranged on both surfaces of the aluminum foil layer.

[0144] Furthermore, when the first packaging layer 131 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 the packaging layer provides both better isolation when rupture is not necessary and better, more timely rupture in the event of thermal runaway.

[0145] 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.

[0146] In some examples, the first encapsulation layer 131 includes a polypropylene layer, an aluminum foil layer, a nylon layer, and a polyester layer stacked from the inside out. 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 1312 may extend from one side of the polyester layer to half the thickness of the aluminum foil layer.

[0147] In some embodiments, the composite thermal insulation pad 10 further includes an adhesive layer, and the thermal insulation pad body 11 and the first packaging layer 131 are connected via the adhesive layer.

[0148] In some embodiments, the thickness of the thermal conductive layer 12 accounts for 70% to 96% of the total thickness of the package thermal conductive layer; as an example, the thickness may account for 70%, 75%, 80%, 86%, 90%, 92%, 95%, 96%, and further, may be 86% to 96%.

[0149] It can be understood that the total thickness of the package heat-conducting layer includes the sum of the thicknesses of the first package layer 131 on one side, the heat-conducting layer 12 , and the first package layer 131 on the other side in the thickness direction.

[0150] In some embodiments, the thickness of the package thermal conductive layer is 1mm to 6mm, and can be 1mm to 4mm. As an example, it can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 5mm, or 6mm. It can also be 1.5mm to 3.5mm.

[0151] In some embodiments, the thickness ratio of the package heat conductive layer to the thermal insulation pad body 11 is 0.15-12:1, further 0.5-8:1, for example 0.15:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1.

[0152] It is understood that when the encapsulated thermally conductive layer is completely embedded in the thermal insulation pad body 11, the thickness of the thermal insulation pad body 11 is greater than the thickness of the encapsulated thermally conductive layer. When the encapsulated thermally conductive layer is located between two thermal insulation layers, and the thermally conductive layer 12 does not protrude from the thermal insulation layers, or in other embodiments, the thickness of the encapsulated thermally conductive layer can be greater than the thickness of the thermal insulation pad body 11, or it can be less than or equal to the thickness of the thermal insulation pad body 11.

[0153] Furthermore, the thickness of the thermal insulation pad body 11 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.

[0154] In some embodiments, the length and width of the thermal insulation pad body 11 are respectively adapted to the length and width of the encapsulated thermal conductive layer, i.e., the length and width are equal. In other embodiments, at least one of the length and width of the thermal insulation pad body 11 is greater than the corresponding length or width of the encapsulated thermal conductive layer.

[0155] See also Figure 5 In some embodiments, the encapsulation layer further includes a second encapsulation layer 132. The second encapsulation layer 132 is disposed on the outer periphery of the thermal insulation pad body 11, constituting an encapsulated thermal insulation layer. In other words, the encapsulated thermal insulation layer includes the thermal insulation pad body 11 and the second encapsulation layer 132, which is disposed on the outer periphery of the thermal insulation pad body 11. Accordingly, the second encapsulation layer 132 of the encapsulated thermal insulation layer contacts the thermal conductive layer 12.

[0156] It can be understood that the second packaging layer 132 separately packages the thermal insulation pad body 11 , and does not package the heat-conducting layer 12 .

[0157] The second packaging layer 132 can play a certain packaging and protection role for the thermal insulation pad body 11, and can further reduce the problem of impurities entering the thermal insulation pad body 11 to form a heat conduction path and affect the thermal insulation performance, thereby further improving the thermal insulation performance of the above-mentioned composite thermal insulation pad 10. When applied to batteries, it has a good effect of preventing battery thermal runaway.

[0158] Similarly, the second encapsulation layer 132 has a second encapsulation margin portion 1321 (see Figure 7 ) can form a pressed edge structure by pressing the edge.

[0159] Furthermore, the second packaging margin portion 1321 can also be folded and positioned between the packaging heat-insulating layer and the heat-conducting layer 12 , so that each side of the packaging film forms a wrapping structure.

[0160] Furthermore, the second packaging layer 132 is an aluminum-plastic film or a polymer packaging film, including but not limited to a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0161] In a specific example, the first encapsulation layer 131 is an aluminum-plastic film, and the second encapsulation layer 132 is a polymer encapsulation film.

[0162] Furthermore, the thickness of the second packaging layer 132 is 0.05 mm to 0.1 mm; optionally 0.07 mm to 0.09 mm, and further 0.08 mm ± 0.005 mm.

[0163] See also Figure 6 In some embodiments, the encapsulation layer further includes a third encapsulation layer 133. The third encapsulation layer 133 is provided on the common peripheral side of the thermal insulation pad body 11 and the heat-conducting layer 12. In other words, unlike the first encapsulation layer 131 which is provided solely on the heat-conducting layer 12, and the second encapsulation layer 132 which is provided solely on the thermal insulation pad body 11, the third encapsulation layer 133 is partially provided on the thermal insulation pad body 11 and partially provided on the heat-conducting layer 12, so as to encapsulate the thermal insulation pad body 11 and the heat-conducting layer 12 together. That is, the third encapsulation layer 133 is provided on the peripheral side of the thermal insulation pad body 11 and the heat-conducting layer 12 as a whole to constitute an encapsulated thermal insulation layer. In this way, the entire composite thermal insulation pad is encapsulated and protected as a whole by the third encapsulation layer 133.

[0164] It can be understood that if the thermal conductive layer 12 is embedded in the thermal insulation pad body 11 , the common peripheral side of the thermal insulation pad body 11 and the thermal conductive layer 12 is the surface of the thermal insulation pad body 11 exposed to the outside, which does not include the inner surface in contact with the thermal conductive layer 12 .

[0165] Furthermore, the third encapsulation layer 133 is an aluminum-plastic film or a polymer encapsulation film, including but not limited to a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0166] In a specific example, the third encapsulation layer 133 is an aluminum-plastic film, and the third encapsulation layer 133 is a polymer encapsulation film.

[0167] Furthermore, the thickness of the third encapsulation layer 133 is 0.05 mm to 0.1 mm; optionally 0.07 mm to 0.09 mm, and further 0.08 mm ± 0.005 mm.

[0168] It is understood that, in a specific example, the encapsulation layer may only include the third encapsulation layer 133 , without the first encapsulation layer 131 and the second encapsulation layer 132 .

[0169] Furthermore, in a specific example, the encapsulation layer may include both the first encapsulation layer 131 and the third encapsulation layer 133. Thus, the phase change material layer 121 in the first encapsulation layer 131 may be made of at least one of liquid, semi-solid or solid phase change materials.

[0170] Furthermore, in another specific example, the encapsulation layer may include both the second encapsulation layer 132 and the third encapsulation layer 133 .

[0171] See also Figure 7 In another specific example, the encapsulation layer may include the first encapsulation layer 131 and the second encapsulation layer 132. The first encapsulation margin 1311 of the first encapsulation layer 131 and the second encapsulation margin 1321 of the second encapsulation layer 132 may adopt a pressed edge structure. Figure 8 The first packaging margin 1311 of the first packaging layer 131 and the second packaging margin 1321 of the second packaging layer 132 may adopt a hemming structure.

[0172] Furthermore, in another specific example, the encapsulation layer includes the first encapsulation layer 131, the second encapsulation layer 132, and the third encapsulation layer 133. It is understood that when the third encapsulation layer 133 is provided, it is preferable that the first encapsulation margin 1311 of the first encapsulation layer 131 and the second encapsulation margin 1321 of the second encapsulation layer 132 adopt a hemming structure, and the fold is located between the layer structures of the composite thermal insulation pad 10, which can facilitate the encapsulation operation of the third encapsulation layer 133.

[0173] It is understandable that the first encapsulation layer 131 , the second encapsulation layer 132 and the third encapsulation layer 133 may adopt any one of them or a combination of multiple ones according to different scene requirements.

[0174] Please continue reading Figure 3In some embodiments, the thermal insulation pad body 11 includes a first thermal insulation layer 111 and a second thermal insulation layer 112 located on either side of the thermal conductive layer 12 in the thickness direction, such that the thermal conductive layer 12 is sandwiched within the thermal insulation pad body 11. In other words, the first thermal insulation layer 111, the thermal conductive layer 12, and the second thermal insulation layer 112 are stacked in sequence. The thermal conductive layer 12 is disposed between the first thermal insulation layer 111 and the second thermal insulation layer 112. The thermal conductive layer 12 can absorb heat transferred from the thermal insulation layers on both sides and diffuse it to the surrounding area, thereby further improving the thermal insulation and heat dissipation performance of the composite thermal insulation pad.

[0175] Furthermore, the strain of the first and second insulation layers 111 and 112 when subjected to a stress of 0.5 to 5 MPa is 25% to 70%. Furthermore, the strain of the sample when subjected to a stress of 0.5 to 3 MPa is 25% to 70%, and even more so, the strain of the sample when subjected to a stress of 0.5 to 2.8 MPa is 29% to 57%. The first and second insulation layers have certain compressibility, which can absorb battery expansion when the battery expands, thereby further improving the service life and thermal insulation performance of the insulation mat.

[0176] 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.

[0177] 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.

[0178] Strain is the percentage value of the thickness change of the sample under stress relative to the initial thickness of the sample. The thickness change of the sample under stress is recorded by a micrometer or pressure tester relative to the initial position. The equipment used for the initial thickness of the sample is as follows: Mitutoyo 547-301 thickness gauge, equipment accuracy: ≤0.01mm; during testing, the test surfaces of the composite insulation pad and Mitutoyo 547-301 thickness gauge are required to remain parallel to the ground. The test positions are 5 points in total, including the four corners and the center area, and the average value of the 5 points is taken as the test value. That is, strain = displacement recorded by the micrometer or pressure tester / initial thickness of the sample.

[0179] 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.

[0180] Furthermore, the composite thermal insulation pad 10 includes a first thermal insulation layer 111, a second thermal insulation layer 112, and a thermally conductive layer 12 sandwiched between the first and second thermal insulation layers 111 and 112. The composite thermal insulation pad 10 exhibits a strain of 15% to 35% when subjected to a stress of 0.5 to 4 MPa. This composite thermal insulation pad 10 exhibits both excellent compressive and thermal insulation properties, enabling it to be used in a battery insulation structure with excellent thermal insulation properties, preventing the spread of thermal runaway and absorbing battery expansion, reducing the risks associated with battery expansion.

[0181] Furthermore, in some examples, the heat-conducting layer 12 and the first packaging layer 131 form the aforementioned packaging heat-conducting layer.

[0182] Furthermore, in some examples, the second encapsulation layer 132 is provided on the outer periphery of the first thermal insulation layer 111. Furthermore, in some examples, the second encapsulation layer 132 is provided on the outer periphery of the second thermal insulation layer 112.

[0183] Furthermore, in some examples, the third encapsulation layer 133 is provided on the entirety of the first thermal insulation layer 111 , the thermal conductive layer 12 , and the second thermal insulation layer 112 .

[0184] See also Figure 9 In some embodiments, the composite thermal insulation pad 10 further includes an adhesive layer, and at least one of the first thermal insulation layer 111 and the second thermal insulation layer 112 of the thermal insulation pad body 11 is connected to the thermal conductive layer 12 through the adhesive layer. Furthermore, the adhesive layer includes a first adhesive layer 151 and a second adhesive layer 152. The first thermal insulation layer 111 is connected to the thermal conductive layer 12 through the first adhesive layer 151; the second thermal insulation layer 112 is connected to the thermal conductive layer 12 through the second adhesive layer 152. In this way, the first thermal insulation layer 111, the encapsulated thermal conductive layer and the second thermal insulation layer 112 of the composite thermal insulation pad 10 are connected and fixed in the thickness direction through the adhesive layer.

[0185] Furthermore, the material of the first adhesive layer 151 and the second adhesive layer 152 is independently a silicone adhesive layer, and the thickness is independently 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 prepared composite thermal insulation pad is greater than 10N / 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° to the two sides of the composite thermal insulation pad outward. 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.

[0186] In some embodiments, the composite thermal insulation pad 10 further includes a third thermal insulation layer (not shown), and a thermal conductive layer 12 is also provided between the second thermal insulation layer 112 and the third thermal insulation layer. Furthermore, the composite thermal insulation pad 10 may further include more thermal insulation layers, each of which may also have the aforementioned thermal conductive layer 12 provided between adjacent thermal insulation layers.

[0187] Furthermore, the selection range of materials and thicknesses of the third thermal insulation layer and other thermal insulation layers can be the same as that of the first thermal insulation layer 111 and the second thermal insulation layer 112; the specific materials and specific thicknesses can be the same or different.

[0188] In some embodiments, the composite thermal insulation pad 10 further includes a release adhesive layer (not shown). The release adhesive layer includes a third adhesive layer and a release film. The third adhesive layer is provided on the thermal insulation pad body 11, such as the outer surface of the first thermal insulation layer 111 and / or the second thermal insulation layer 112, and the release film is provided on the outer surface of the third adhesive layer. In this way, when the composite thermal insulation pad 10 needs to be fixed to a target position, such as a target battery cell, the release film on the surface of the release adhesive layer on the composite thermal insulation pad 10 is removed, and it is simply and conveniently fixed to the target position by bonding with the third adhesive layer, which can fix the composite thermal insulation pad 10.

[0189] As an example, the aforementioned release adhesive layers are provided on the outer surfaces of the first insulation layer 111 and the second insulation layer 112 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.

[0190] Please continue reading Figure 3 The composite thermal insulation pad 10 may further include a strain detection member 17. The strain detection member 17 is provided in the thermal insulation pad body 11. Further, the strain detection member 17 is provided inside the thermal insulation pad body 11, or on the outer surface of the thermal insulation pad body 11.

[0191] It is understood that the strain detection member 17 may be disposed within the thermal insulation pad body 11, including but not limited to a portion or the entirety of the strain detection member 17 being located within the thermal insulation pad body 11. The entirety of the strain detection member 17 being located within the thermal insulation pad body 11 includes but is not limited to a portion of the surface of the strain detection member 17 being flush with the thermal insulation pad body 11, i.e., the portion of the surface is not covered by the thermal insulation layer and is exposed, and also includes a situation where the entire surface of the strain detection member 17 is covered by the thermal insulation pad body 11, i.e., the strain detection member 17 is entirely located within the thermal insulation pad body 11.

[0192] The strain detector 17 is a component used to detect stress parameters. Generally, it includes a flexible layer and a strain detection element layer provided 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 thermal insulation pad 10 can be obtained based on the electrical signal output by the strain detector 17, that is, the stress experienced by the composite thermal insulation pad 10 can be monitored. For example, the volume of a battery cell expands during use, which causes the pressure between adjacent battery cells to change. In this way, when the composite thermal insulation pad 10 is used in a battery, the expansion state of the battery during use can be determined through the strain detector 17. In addition, the packaging layer of the composite thermal insulation pad 10 will also cause the pressure between adjacent battery cells to change before and after failure. Therefore, the strain detector 17 can also be used to determine whether the packaging layer has collapsed and failed during battery use. In this way, the strain detector 17 provided in the composite thermal insulation pad 10 can accurately obtain the state of the battery during use.

[0193] Specifically, the strain detection element 17 may be provided in at least one of the first thermal insulation layer 111 and the second thermal insulation layer 112 .

[0194] In some examples, by applying pressure to the thermal insulation pad 10, strain is generated. As the strain increases from 0 to point A, the greater the strain, the greater the stress detected by the strain detection element 17. This is the deformation state of the packaging layer in the thermal insulation pad 10 before failure. When point A is reached, pressure is continued to be applied, and the strain continues to increase, but the stress detected by the strain detection element 17 decreases. This is because the external pressure is too large, causing the packaging layer 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 thermal insulation pad 10 can be known by the stage of the stress curve detected by the strain detection element 17. When applied to batteries, the state of the battery cells adjacent to the thermal insulation pad 10 can also be known.

[0195] In such Figure 3 In the specific example, the strain detection element 17 is provided in the first thermal insulation layer 111, and the strain detection element 17 is entirely located within the first thermal insulation layer 111. It is understood that the strain detection element 17 may also be provided in the second thermal insulation layer 112, or the strain detection element 17 may also be provided in both the first thermal insulation layer 111 and the second thermal insulation layer 112.

[0196] Furthermore, the strain detector 17 has a first surface away from the thermally conductive layer 12, and the thermal insulation pad body 11 equipped with the strain detector 17 has a second surface away from the thermally conductive layer 12. 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 further away from the phase change material layer 121. This allows the thermal insulation pad to protect the strain detector 17 while maintaining its sensitivity.

[0197] It can be understood that the strain detection element 17 is provided on the surface of the thermal insulation pad body 11 , which surface may be the surface opposite to the phase change material layer 121 or the surface opposite to the phase change material layer 121 .

[0198] Optionally, the strain detector 17 is disposed on the outer surface of the thermal insulation pad body 11, thereby enabling a more rapid response to stress changes. Furthermore, the thermal insulation pad 10 may also include a waterproof protective film (not shown) disposed on the outer surface of the strain detector 17 to protect it from moisture and extend its service life.

[0199] 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.

[0200] 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.

[0201] In some embodiments, the ratio of the thickness of the strain detection member 17 to the thickness of the thermal insulation pad body 11 is 1:(500-10).

[0202] 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.

[0203] See also Figure 9 The first thermal insulation layer 111 and the second thermal insulation layer 112 are physically isolated by the thermal conductive layer 12; in other words, the thermal conductive layer 12 is partially surrounded by the thermal insulation pad body 11, and the edges between the first thermal insulation layer 111 and the second thermal insulation layer 112 are not connected to each other, but the thermal conductive layer 12 is located inside the thermal insulation pad body 11.

[0204] See also Figure 10In some embodiments, the edges of the first thermal insulation layer 111 and the second thermal insulation layer 112 are connected to form an assembly cavity, and the thermal conductive layer 12 is located within the assembly cavity. With this structural arrangement, the thermal conductive layer 12 is located within the first thermal insulation layer 111 and the second thermal insulation layer 112, reducing the risk of the thermal conductive layer 12 falling off.

[0205] Furthermore, the edge of at least one side surface of at least one of the first thermal insulation layer 111 and the second thermal insulation layer 112 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 111 and the second thermal insulation layer 112 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 3 In a specific example, convex portions are formed on the four edges of one side surface of the first thermal insulation layer 111 and the second thermal insulation layer 112, and the convex portions of the first thermal insulation layer 111 and the second thermal insulation layer 112 are arranged opposite to each other and enclosed to form an assembly cavity.

[0206] Furthermore, in Figure 10 In the specific example, since the structures of the first thermal insulation layer 111 and the second thermal insulation layer 112 are irregular, the first encapsulation layer 131 can be used to encapsulate the thermal conductive layer, which is easier to operate. Furthermore, the third encapsulation layer 133 can be used to encapsulate the thermal conductive layer 12 and the first thermal insulation layer 111 and the second thermal insulation layer 112 as a whole.

[0207] Furthermore, in Figure 10 In a specific example, when the heat-conducting layer 12 is disposed inside the first heat-insulating layer 111 and the second heat-insulating layer 112 , the first package margin portion 1311 is folded and located in the assembly cavity.

[0208] See also Figure 11 and Figure 12 In some embodiments, the composite thermal insulation pad 10 further includes a first packaging frame 141 and a second packaging frame 142 , and the first packaging frame 141 and the second packaging frame 142 cooperate to fix the thermal conductive layer 12 , the thermal insulation pad body 11 and the packaging layer.

[0209] Furthermore, the first packaging frame 141 is arranged on one side of the first insulation layer 111, and the second packaging frame 142 is arranged on one side of the second insulation layer 112. The first packaging frame 141 and the second packaging frame 142 cooperate to fix the first insulation layer 111, the heat conducting layer 12, the packaging layer and the second insulation layer 112.

[0210] Furthermore, the first packaging frame 141 and the second packaging frame 142 are each independently made of a rubber frame or a silicone frame, which has good flexibility and can absorb the expansion force caused by battery expansion. In other words, the material of 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 each independently made of a square frame, such as a square silicone frame.

[0211] In some specific examples, the encapsulation layer further includes the aforementioned first encapsulation layer 131 and second encapsulation layer 132, which respectively encapsulate the thermally conductive layer 12, the first thermally insulating layer 111, and the second thermally insulating layer 112. In this case, the first encapsulation frame 141 and the second encapsulation frame 142 are connected, resulting in a more stable structure. Furthermore, the thermally conductive layer 12 may utilize a liquid or semi-solid phase change material.

[0212] Furthermore, 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). The first thermal insulation layer 111, the thermal conductive layer 12, the packaging layer, and the second thermal insulation layer 112 are limited within 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 thermal conductive layer 12, the thermal insulation pad body 11, and the packaging layer in the thickness direction and radial direction of the composite thermal insulation pad 10, thereby improving the structural stability of the composite thermal insulation pad 10.

[0213] 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. Furthermore, at this time, the first packaging margin portion 1311 of the first packaging layer 131 can be located between the first packaging frame 141 and the second packaging frame 142, and pressed by the side walls of the first packaging frame 141 and the second packaging frame 142.

[0214] 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 111 and second thermal insulation layer 112 that can form an assembly cavity are provided at the same time, the first packaging margin 1311 of the first packaging layer 131 can pass through between the convex portions of the first thermal insulation layer 111 and the second thermal insulation layer 112 and be located between the first packaging frame 141 and the second packaging frame 142, or the first packaging margin 1311 of the first packaging layer 131 can also be folded and located in the assembly cavity.

[0215] See also Figure 1 In (a), in some embodiments, the thermal insulation pad body 11 is provided with a hollow cavity, and a solid phase change material layer is provided in the hollow cavity. Since the solid phase change material is provided in the thermal insulation pad body 11, it will not affect the thermal insulation performance of the thermal insulation substrate under normal conditions, so the second encapsulation layer 132 may not be provided on the outside of the thermal insulation pad body 11. Furthermore, the encapsulation layer may also only include the above-mentioned first encapsulation layer 131 to encapsulate and protect the thermal conductive layer 12 therein. Of course, the encapsulation layer may also include the above-mentioned first encapsulation layer 131 and the second encapsulation layer 132 to encapsulate the thermal conductive layer 12 and the thermal insulation pad body 11 respectively. At this time, the connection method of the first encapsulation frame 141 and the second encapsulation frame 142 is adopted, and the structure is relatively stable. Furthermore, liquid or semi-solid phase change material can be used in the thermal conductive layer 12.

[0216] See also Figure 13 In other embodiments, the outer surface of the first thermal insulation layer 111 is flush with the outer surface of the first packaging frame 141, and / or the outer surface of the second thermal insulation layer 112 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.

[0217] As an example, in addition to 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 phase change material layer 121, the thermal insulation pad body 11, and the periphery of the packaging layer, thereby improving the structural stability of the composite thermal insulation pad 10. Furthermore, in this case, the packaging frame is not required to secure the thickness direction, so that the outer surface of the first thermal insulation layer 111 can be flush with the outer surface of the first packaging frame 141, and the outer surface of the second thermal insulation layer 112 can be flush with the outer surface of the second packaging frame 142.

[0218] It can be understood that in some embodiments, the first thermal insulation layer 111, the thermal conductive layer 12, the second thermal insulation layer 112, and the third thermal insulation layer can be connected by the above-mentioned adhesive layer instead of the above-mentioned packaging frame, or connected by the above-mentioned packaging frame instead of the above-mentioned adhesive layer, or connected by both the above-mentioned adhesive layer and the packaging frame, or none of them, for example, the first thermal insulation layer 111 can be directly formed on the surface of the thermal conductive layer 12 in the form of a coating.

[0219] Furthermore, the first thermal insulation layer 111 , the second thermal insulation layer 112 and the third thermal insulation layer each independently include at least one of thermal insulation felt and thermal insulation coating.

[0220] 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 thermally conductive layer 12. Specifically, the thermal insulation coating is disposed on the surface of the first encapsulation layer 131 of the thermally conductive layer 12, while the thermal insulation felt is disposed on a side further away from the thermally conductive layer 12. In other words, the thermal insulation coating is formed directly on the surface of the first encapsulation layer 131 and is located between the first encapsulation layer 131 and the thermal insulation felt.

[0221] For example, Figure 3 In the example, the first thermal insulation layer 111 and the second thermal insulation layer 112 are thermal insulation felt, and the third thermal insulation layer is also thermal insulation felt. In other examples, the first thermal insulation layer 111 and the second thermal insulation layer 112 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 smaller occupied space and better thermal insulation performance.

[0222] by Figure 3 For example, when the strain detector 17 is provided in the second thermal insulation layer 112, a groove for accommodating the strain detector 17 can be first opened in the first thermal insulation layer 111. After the strain detector 17 is placed in the groove, thermal insulation felt is filled to cover the strain detector 17. Specifically, the strain detector 17 and the thermal insulation felt can be fixed by an adhesive layer.

[0223] For example, in Figure 10 In the example shown, the first insulation layer 111 and the second insulation layer 112 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.

[0224] It is understood that the thermal insulation felt can be connected to the thermally conductive layer 12 via the aforementioned adhesive layer or packaging frame. The thermal insulation coating can be formed directly on the first packaging layer 131 of the thermally conductive layer 12. As an example, the thermal insulation coating can be formed by coating the first packaging layer 131 of the thermally conductive layer 12 with a slurry and then drying it to form a coating.

[0225] Furthermore, the thermal insulation felt can be a ceramic thermal insulation felt; furthermore, the thermal insulation coating can be a ceramic thermal insulation coating. It is understood that both the ceramic thermal insulation felt and the ceramic thermal insulation coating are layers of ceramic material. In some embodiments, the thermal insulation pad body 11 is a ceramic material layer. In other words, the first thermal insulation layer 111, the second thermal insulation layer 112, and the third thermal insulation layer are each independently a ceramic material layer.

[0226] 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. The ceramic oxides include, but are not limited to, at least one of silicon oxide and aluminum oxide, the ceramic nitrides include, but are not limited to, silicon nitride, and the ceramic carbides include, but are not limited to, silicon carbide.

[0227] 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.

[0228] 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.

[0229] In some embodiments, the first thermal insulation layer 111, the second thermal insulation layer 112 and the third thermal insulation layer 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.

[0230] In some embodiments, the density of the first thermal insulation layer 111, the second thermal insulation layer 112, and the third thermal insulation layer is independently 0.2 to 0.22 g / cm 3 Furthermore, the thickness of the first heat insulation layer 111 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, or 8 mm; it can optionally be 1 mm to 8 mm.

[0231] Furthermore, the thickness of the second heat insulation layer 112 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.

[0232] 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.

[0233] In some embodiments, the phase change material layer 121 may include a heat-insulating substrate in addition to the phase change material, and the phase change material is filled in the heat-insulating substrate. In other words, the pores of the heat-insulating substrate are filled with the phase change material.

[0234] The thermal insulation substrate may be a ceramic material substrate, such as ceramic fiber felt.

[0235] Furthermore, in some examples, at least a portion of the phase change material is directly filled into the pores of the thermal insulation substrate. 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.

[0236] It is understood that the phase change material layer 121 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 121 can also provide thermal insulation. When the phase change material vaporizes and breaks through the first encapsulation layer 131, that is, the composite thermal insulation pad 10 fails, the thermal insulation substrate in the phase change material layer 121 can continue to provide thermal insulation. In other words, the phase change material is directly filled in the pores of the thermal insulation substrate.

[0237] In other embodiments, 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. In other words, the pores of the thermal insulation substrate of the phase change material layer 121 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, wherein the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material. It is understood that in some examples, the pores of the thermal insulation substrate can also be directly filled with the phase change material and the aforementioned phase change microcapsules at the same time.

[0238] The above-mentioned phase change material layer 121 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 removing the solvent in the phase change microcapsule dispersion.

[0239] In this way, the phase change microcapsules in the phase change material layer 121 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 first packaging layer 131, that is, the composite thermal insulation pad 10 fails. At this time, the thermal insulation substrate in the phase change material layer 121 can continue to play a thermal insulation role.

[0240] Furthermore, the wall material includes a polymer matrix and ceramic particles filled in the polymer matrix. Furthermore, the mass ratio of the polymer matrix to the ceramic particles is 3:(7-11). As an example, the mass ratio of the polymer matrix to the ceramic particles can be 3:7, 3:8, 3:9, 3:10, or 3:11. By controlling the mass content of ceramic particles in the wall material to be relatively high, the pressure resistance and thermal insulation capabilities of the wall material can be improved.

[0241] Furthermore, the mass ratio of the polymer matrix to the core material is 1:(1.3-1.6). As an example, the mass ratio of the polymer matrix to the core material can be 1:1.3, 1:1.4, 1:1.5, or 1:1.6. This can further improve the pressure resistance of the phase change microcapsules.

[0242] Furthermore, the polymer matrix includes, but is not limited to, any one of phenolic resin, polyacrylonitrile resin, melamine formaldehyde resin, etc. The polymer matrix not only has good insulation properties, but also has good compatibility with phase change materials such as paraffin wax, and can form a stable interface with the phase change material, thereby improving the thermal stability of the phase change microcapsules.

[0243] Furthermore, the phase-change microcapsules have a Dv50 particle size of 5 to 8 μm. The Dv50 particle size, also known as the volume average particle size (Dv50), represents the particle size at which 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., Malvern Master Size 3000).

[0244] Furthermore, the thermal conductivity of the wall material at 25° C. is ≥0.32 W / m·K. Such a wall material has a good thermal conductivity and can better conduct heat to the phase change material inside it.

[0245] 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.

[0246] The material selection of the above-mentioned thermal insulation substrate and ceramic particles in this application is the same as the selection range of the above-mentioned ceramic material layer. In some examples, the above-mentioned thermal insulation substrate is a ceramic fiber mat. The ceramic fiber mat has ceramic fiber as the core skeleton, which can not only well infiltrate the liquid phase change material so that the phase change material is filled in the pores of its core skeleton, but also has low thermal conductivity, good high temperature resistance (1280°C), resistance to instantaneous thermal shock, flame retardant properties and mechanical properties, no powdering, and is flexible and resilient, and is compatible with the battery pack manufacturing process.

[0247] 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.

[0248] Furthermore, the average diameter of the nano-ceramic fibers is 200 to 800 nm, and the thickness of the thermal insulation substrate is 1 mm to 2 mm.

[0249] 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.

[0250] Phase-change microcapsules can be obtained by in-situ polymerization, where the wall material is coated with the core material. In some examples, the preparation method of 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 phase and the oil phase and stirring to form a Pickering emulsion; adding the raw materials required to prepare the polymer matrix of the wall material (such as water-soluble polymer monomers or prepolymer aqueous solutions) to the Pickering emulsion; and stirring and polymerizing at room temperature to form a non-water-soluble condensation polymer (i.e., polymer matrix) with a cross-linked three-dimensional network structure at the emulsion interface.

[0251] The polymer matrix of the above materials has better compatibility with phase change materials such as paraffin wax, and also facilitates the uniform dispersion of ceramic particles, ensuring the stability of phase change microcapsules. Figure 4 The first encapsulation layer 131 is provided on the thermally conductive layer 12 to form an encapsulated thermally conductive layer, and the thermally conductive layer 12 includes a phase change material layer 121. Furthermore, the phase change material layer 121 includes the aforementioned thermal insulation substrate 1211 and a phase change material filling the pores of the thermal insulation substrate 1211. Furthermore, a gap exists between at least one side edge 1211a of the thermal insulation substrate 1211 located within the encapsulation cavity formed by the first encapsulation layer 131 and the inner wall 131a of the encapsulation cavity. A weak portion 1312 is provided on the first encapsulation layer 131 and is located between the edge 1211a of the thermal insulation substrate 1211 and the inner wall 131a of the encapsulation cavity.

[0252] In some embodiments, the phase change material layer 121 includes the above-mentioned thermal insulation substrate 1211 and the phase change material filled in the pores of the thermal insulation substrate 1211; the strain of the encapsulated thermal conductive layer when subjected to a stress of 0.5 to 5 MPa is 8% to 20%. Furthermore, the strain of the encapsulated thermal conductive layer when subjected to a stress of 0.5 to 4 MPa is 8% to 20%, and further approximately 9% to 15.5%. The encapsulated thermal conductive layer has certain compression properties and can absorb battery expansion when the battery expands, thereby further improving the service life and thermal insulation performance of the thermal insulation pad. In some embodiments, in addition to the phase change material, the phase change material layer 121 may also include at least one of an infrared shielding agent, a flame retardant, and a thermal conductor, which may also be further filled in the pores of the thermal insulation substrate. Among them, 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 20W / (mK).

[0253] 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 121 may be formed by forming a mixed solution of the phase change material and at least one of an infrared shielding agent, a flame retardant, and a thermal conductor, then immersing the thermal insulation substrate in the mixed solution, and then drying or heat-insulating the solution.

[0254] It can be understood that because the first encapsulation layer 131 is provided on the outer surface of the phase change material layer 121 and forms an encapsulation cavity, the first encapsulation layer 131 includes a first region in contact with the first thermal insulation layer 111, a second region in contact with the second thermal insulation layer 112, and a third region connecting the first and second regions. The weak portion 1312 is provided in the first and / or second regions of the first encapsulation layer 131 and is located between the edge 1211a of the thermal insulation substrate 1211 and the inner wall 131a of the encapsulation cavity, that is, located in the region of the first encapsulation layer 131 forming the aforementioned gap. The inner wall 132a of the encapsulation cavity herein refers to the inner wall of the encapsulation cavity directly opposite the side edge 1211a of the thermal insulation substrate 1211, that is, the third region directly opposite the side edge 1211a of the thermal insulation substrate 1211.

[0255] Furthermore, the two opposite surfaces of the thermal insulation substrate 1211 are bonded to the opposite inner walls of the first packaging layer 131, that is, the two opposite surfaces of the thermal insulation substrate 1211 are bonded to the first area and the second area of the packaging layer, respectively. The side edge of the thermal insulation substrate 1211 is the edge connecting the two opposite surfaces of the thermal insulation substrate 1211. The thermal insulation substrate 1211 is square, and there is a gap between the side edges on all sides and the inner walls on all sides of the packaging cavity. In other words, the above-mentioned gap surrounds the four edges of the thermal insulation substrate 1211. Reserving this gap can, on the one hand, prevent the stress between the four edges of the thermal insulation substrate 1211 and the packaging layer from being too great to cause damage to the packaging layer, and on the other hand, reserve a certain volume change space for the phase change material therein.

[0256] Furthermore, the distance h1 between the weak portion 1312 and the edge 1211a of the thermal insulation substrate 1211 is controlled to be 2-7 mm, optionally 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 1211.

[0257] 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 ensure that the first packaging layer 131 is ruptured and gas is discharged 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.

[0258] Furthermore, the weak portion 1312 is linear. Furthermore, the extension direction of the weak portion 1312 is the same as the extension direction of the edge 1211a of the thermal insulation substrate 1211. It is understood that in other examples, the weak portion 1312 may also be arc-shaped, etc., and is not limited thereto.

[0259] Furthermore, the total length of the weak portion 1312 accounts for 50% to 100% of the length of the edge of the thermal insulation substrate 1211, and can be 50% to 80%. For example, the length ratio can be 50%, 60%, 70%, 80%, 90%, or 100%. The total length ratio of the weak portion 1312 is controlled to ensure that thermal runaway occurs and the package is broken in a timely manner.

[0260] Furthermore, there are multiple weak portions 1312, which are spaced apart along the extending direction of the edge 1211a of the thermal insulation substrate 1211. The length of each weak portion 1312 is 1 / 20 to 1 / 10 of the edge 1211a of the thermal insulation substrate 1211, for example, 1 / 20, 1 / 15, or 1 / 10.

[0261] In a specific example, the weak portion 1312 is a notched area, and the length of the weak portion 1312 is 5 to 20 mm, and the width of the weak portion 1312 is 0.5 to 2 mm.

[0262] It is understandable that the technical solutions of the multiple embodiments described above can be combined and applied without conflicting with each other.

[0263] See also Figure 14 and Figure 15 Another embodiment of the present application further provides a battery 30, which includes any of the above-mentioned composite thermal insulation pads 10.

[0264] 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.

[0265] 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.

[0266] 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 insulation pad body 11 (the first insulation layer 111 and / or the second insulation layer 112) 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.

[0267] 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 thermal conductive layer 12 in the composite thermal insulation pad 10 absorbs and conducts heat, the phase change material layer 121 in the thermal conductive layer 12 absorbs heat, and the intermediate layer 122 in the thermal conductive layer 12 conducts heat quickly, triggering the phase change material layer 121 to absorb heat over a larger area, thereby achieving the effect of slowing down the thermal runaway of the battery. In the second stage, the phase change material layer 121 absorbs heat until a phase change occurs, absorbing a large amount of heat. In the third stage, the first packaging layer 131 and the phase change material layer 121 fail: the phase change material in the phase change material layer 121 is converted into gas and breaks the first packaging layer 131, discharging the high-temperature gas. In the fourth stage, the first thermal insulation layer 111 and the second thermal insulation layer 112 and the thermal insulation substrate in the phase change material layer 121 continue to play a role in thermal insulation.

[0268] Among them, the first stage and the second stage are the states before the composite thermal insulation pad 10 fails, and the third stage and the fourth stage are the states after the composite thermal insulation pad 10 fails.

[0269] 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.

[0270] In some embodiments, the battery cell 20 is square, and the composite thermal insulation pad 10 is disposed on a side surface of the battery cell 20 with a larger area to increase its contact area and improve the thermal insulation performance.

[0271] Furthermore, the composite thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0272] 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.

[0273] 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.

[0274] For example, Figure 16The figure shows a battery cell 20 with 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, and the cover plate 23 is sealed at 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.

[0275] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0276] Furthermore, the housing 21 is a rectangular parallelepiped housing, and the opening of the housing 21 is oriented along the height of the housing 21. Furthermore, the housing 21 has openings at both ends, and the two openings are arranged opposite each other along the height of the housing 21. Further, 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; further, as a non-limiting example, the width of the housing 21 is 20 mm to 80 mm.

[0277] 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.

[0278] As a further non-limiting example, the wall thickness of the housing is 0.5 mm to 0.8 mm.

[0279] Furthermore, the housing is an aluminum alloy housing; for example, a third-series aluminum alloy housing or a fifth-series aluminum alloy housing.

[0280] 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%.

[0281] 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%.

[0282] 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.

[0283] As an electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0284] Figure 17 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.

[0285] 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.

[0286] 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.

[0287] The following are preparation examples.

[0288] Example 1

[0289] The composite thermal insulation pad 10 of Example 1, such as Figure 9 As shown, it includes a first thermal insulation layer 111, a first adhesive layer 151, a thermal conductive layer 12, a second adhesive layer 152, and a second thermal insulation layer 112 stacked in sequence. The thermal conductive layer 12 includes two phase change material layers 121 and an intermediate layer 122 disposed between the two phase change material layers 121. The intermediate layer 122 is a copper metal layer with a thickness of 0.03 mm.

[0290] The first packaging layer 131 is disposed on the outer surface of the heat-conducting layer 12 to form a packaging heat-conducting layer.

[0291] The first thermal insulation layer 111 and the second thermal insulation layer 112 are both silica aerogel ceramic felts, and both have a thickness of 1.5 mm.

[0292] The thickness of the first adhesive layer 151 and the second adhesive layer 152 are both 0.05 mm; both are made of silicone adhesive layer.

[0293] In the encapsulated heat-conducting layer, the phase change material layer 121 includes a heat-insulating substrate and a phase change material filled in the pores of the heat-insulating substrate. The specific composition of the phase change material is paraffin, specifically C 28 H 58 、C 38 H 78 and C 57 H 116 Phase change material layer 121 has a total phase change material content of 60% by mass. The thermal insulation substrate is silica ceramic fiber felt. The first encapsulation layer 131 is an aluminum-plastic film with a total thickness of 0.3 mm on both sides. The two phase change material layers 121 have the same thickness, and the total thickness of the two phase change material layers 121 and the thermal conductive layer 12 is 3 mm.

[0294] Example 2

[0295] The structure and materials of Example 2 are basically the same as those of Example 1, with the only difference being the structure of the heat-conducting layer 12, specifically, the absence of the intermediate layer 122, ie, the absence of the copper metal layer. The heat-conducting layer 12 is a phase change material layer with a total thickness of 3 mm.

[0296] The following is a performance test.

[0297] The composite thermal insulation pads prepared in each embodiment were tested for thermal insulation performance.

[0298] The test method is as follows: One side of the composite insulation mat is burned with a butane flame for 1200 seconds, while the other side remains untreated. Temperature sensors are installed on opposite sides of the composite insulation mat (a 100mm x 100mm rectangular shape). The real-time temperature of both surfaces is measured over 1200 seconds. The resulting temperature curves are used to determine the insulation effectiveness of the composite insulation mat.

[0299] The side of the composite insulation pad that directly contacts the butane flame is the hot side, and the side opposite the hot side is the cold side. Three temperature sampling points are taken for the hot and cold sides: one at the center, and two others symmetrically spaced 15 mm apart. The average of these three sampling points is used as the real-time temperature value for the hot and cold sides.

[0300] The test results of Example 1 and Example 2 are as follows Figure 18 The temperature change curves of the hot side and the cold side of Example 1 are a1 and a2 respectively. The temperature change curves of the hot side and the cold side of Example 2 are b1 and b2 respectively.

[0301] from Figure 18It can be seen that within the test time of 1200s, when the hot surface temperature reaches nearly 1000℃~1100℃, due to the thermal insulation effect of the composite thermal insulation pad, the maximum temperature of the cold surface in Example 1 is around 100℃, and the maximum temperature of the cold surface in Example 2 does not exceed 300℃. Especially within the first 60s, although the temperature of the hot surface rises, the cold surface has a lower temperature platform (about 50℃). As the test time increases and the heat diffuses further, the temperature of the cold surface rises and basically maintains a temperature platform near 290℃. The phase change platform time is shown in Table 1. Note: The mass in Table 1 refers to the total mass of the composite thermal insulation pad.

[0302] Table 1

[0303]

[0304] Example 3

[0305] It is basically the same as Example 1, with the only difference being that the composition of the phase change material layer in the encapsulated thermal conductive 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.

[0306] Example 4

[0307] This embodiment is essentially the same as Example 1, differing only in the composition of the phase change material in the encapsulated thermal conductive layer. 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. The thermal insulation substrate is also a silica nano-ceramic fiber felt. The main difference is that the phase change material is replaced with an equal mass of crystalline hydrated salt (sodium carbonate decahydrate) and aluminum hydroxide sol. In addition, the phase change material layer 131 also includes an infrared shielding agent filled in the pores of the thermal insulation substrate. The infrared shielding agent includes titanium dioxide and silicon oxide.

[0308] The following is a compression performance test.

[0309] The separate package heat conducting 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 19 As shown, the average strain of the sample under stress of 0.5-5 MPa, further 0.5-4 MPa, is in the range of 8%-20%, further about 9%-15.5%. The package failure rupture pressure of the package thermal conductive layer is slightly greater than 4 MPa.

[0310] The stress-strain test was carried out using the first thermal insulation layer (silica aerogel ceramic felt) in Example 1 as a sample (sample area of 100 mm*100 mm, thickness of 1 mm) to obtain a compression stress-strain curve, as shown in FIG. Figure 20 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.

[0311] The composite thermal insulation pad in Example 1 is used as a sample (the sample area is 100mm*100mm), and multiple groups of parallel stress-strain tests are performed to obtain a stress-strain curve diagram, as shown in FIG. Figure 21 As shown in FIG. 1 , it can be seen that 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.

[0312] The following is a component test of the phase change material layer in the thermal conductive layer of the composite thermal insulation pad of Example 4. Specifically, an electron scanning electron microscope and an energy spectrum analysis (SEM&EDS) were used to obtain SEM and EDS images, as shown in FIG. Figure 22 and Figure 23 The atomic percentage of each element is shown in Table 2:

[0313] Table 2

[0314] element Line Type Wt% Atomic percentage Standard sample labels C K-line system 23.14 31.48 C Vit O K-line system 54.29 55.45 <![CDATA[SiO2]]> Na K-line system 0.68 0.48 Al bite AI K-line system 2.90 1.76 <![CDATA[Al2O3]]> Si K-line system 18.09 10.53 <![CDATA[SiO2]]> Ti K-line system 0.89 0.30 Ti Total / 100.00 100.00 /

[0315] 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.

[0316] 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, all of which 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: Thermal insulation pad body; and The heat-conducting layer is arranged inside the heat-insulating pad body.

2. The composite thermal insulation pad according to claim 1, characterized in that: The heat-conducting layer includes one or a stack of at least two of a phase-change material layer, a metal layer, and a graphene film layer.

3. The composite thermal insulation pad according to claim 2, characterized in that: The heat-conducting layer includes at least two stacked phase-change material layers, and an intermediate layer is provided between at least two of the phase-change material layers. The intermediate layer includes a stack of one or both of a metal layer and a graphene film layer.

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 ratio of the thickness of the intermediate layer to the total thickness of the phase change material layer is (0.3-5):100; (2) The thickness of the intermediate layer is 0.02 mm to 0.04 mm; (3) The projection area of the intermediate layer on the phase change material layer accounts for 90% to 100% of the area of the phase change material layer.

5. The composite thermal insulation pad according to claim 2, characterized in that: The phase change material layer includes a heat insulation substrate and a phase change material, and at least a portion of the phase change material is filled in the heat insulation substrate.

6. The composite thermal insulation pad according to claim 5, 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 hydrated 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 to 800 nm, and the thickness of the thermal insulation substrate is 1 mm to 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); optionally, the thermal insulation substrate is a ceramic thermal insulation substrate; (5) 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; optionally, the wall material includes a polymer matrix, and the mass ratio of the polymer matrix to the core material is 1:(1.3~3); optionally, the Dv50 particle size of the phase change microcapsules is 0.5~8μm.

7. The composite thermal insulation pad according to claim 1, characterized in that: The thermal insulation pad body is provided with a hollow cavity, and the heat conductive layer is provided in the hollow cavity; Optionally, the heat-conducting layer includes a solid phase-change material layer.

8. The composite thermal insulation pad according to any one of claims 1 to 7, characterized in that: The composite thermal insulation pad also includes: The packaging layer is provided on the outer peripheral side of at least one of the heat-conducting layer and the thermal insulation pad body.

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 encapsulation layer includes a first encapsulation layer, which is provided on the outer periphery of the heat-conducting layer and separately encapsulates the heat-conducting layer, and the first encapsulation layer and the heat-conducting layer constitute an encapsulated heat-conducting layer; optionally, the strain of the encapsulated heat-conducting layer when subjected to a stress of 0.5 to 5 MPa is 8% to 20%; (2) The packaging layer further includes a second packaging layer, which is provided on the outer peripheral side of the thermal insulation pad body and separately packages the thermal insulation pad body; (3) The packaging layer further includes a third packaging layer, which is provided on the common outer peripheral side of the thermal insulation pad body and the thermal conductive layer, and packages the thermal insulation pad body and the thermal conductive layer together.

10. The composite thermal insulation pad according to claim 9, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The first encapsulation layer, the second encapsulation layer, and the third encapsulation layer are each independently an aluminum-plastic film or a polymer encapsulation film; (2) The thickness of the first encapsulation layer is 0.1 mm to 0.3 mm; (3) The first packaging layer has a first packaging margin portion, and the first packaging margin portion is folded and arranged inside the thermal insulation pad body; (4) The thickness of the second encapsulation layer and the third encapsulation layer are each independently 0.05 mm to 0.1 mm; (5) The thickness of the thermal conductive layer accounts for 70% to 96% of the total thickness of the package thermal conductive layer; (6) A weak portion is provided on the area of the first packaging layer constituting the packaging cavity; optionally, the heat-conducting layer includes a phase change material layer; optionally, the weak portion is an area with a relatively thin thickness and / or relatively weak material strength; (7) The composite thermal insulation pad also includes a strain detection component, which is arranged on the thermal insulation pad body; optionally, the strain detection component is arranged inside the thermal insulation pad body, or on the outer surface of the thermal insulation pad body.

11. The composite thermal insulation pad according to any one of claims 1 to 7, 9 to 10, characterized in that: The thermal insulation pad body includes a first thermal insulation layer and a second thermal insulation layer located on both sides of the thermal conductive layer in a thickness direction; Optionally, the strain of the first thermal insulation layer and the second thermal insulation layer when subjected to a stress of 0.5 to 5 MPa is 25% to 70%; Optionally, the strain of the composite thermal insulation pad is 15% to 35% when subjected to a stress of 0.5 to 4 MPa.

12. The composite thermal insulation pad according to claim 11, characterized in that: The encapsulation layer includes a second encapsulation layer, and the second encapsulation layer is provided on the outer peripheral side of the first heat insulation layer and / or the outer peripheral side of the second heat insulation layer; And / or, the encapsulation layer includes a third encapsulation layer, and the third encapsulation layer is provided on a common outer peripheral side of the first heat-insulating layer, the heat-conducting layer, and the second heat-insulating layer.

13. The composite thermal insulation pad according to claim 12, characterized in that: The second encapsulation layer has a second encapsulation margin portion, and the second encapsulation margin portion is folded and located between the heat conductive layer and at least one of the first heat insulation layer and the second heat insulation layer.

14. The composite thermal insulation pad according to claim 11, characterized in that: The edges of the first heat-insulating layer and the second heat-insulating layer cooperate with each other to form an assembly cavity, and the heat-conducting layer is located in the assembly cavity.

15. The composite thermal insulation pad according to claim 14, 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.

16. The composite thermal insulation pad according to any one of claims 1 to 7, 9 to 10, and 12 to 15, characterized in that: The composite thermal insulation pad further includes a first packaging frame and a second packaging frame, and the first packaging frame and the second packaging frame cooperate to fix the thermal insulation pad body and the heat conducting layer.

17. The composite thermal insulation pad according to claim 16, characterized in that: The first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the thermal insulation pad body and the thermal conductive layer are limited in a limiting space formed by the first limiting groove and the second limiting groove.

18. The composite thermal insulation pad according to any one of claims 1 to 7, 9 to 10, 12 to 15, and 17, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The thermal insulation pad body is a ceramic material layer; (2) The thickness of the heat-conducting layer is 1 mm to 6 mm; (3) The thickness of the thermal insulation pad body is 0.5mm to 8mm; (4) The ratio of the thickness of the thermal conductive layer to the thickness of the thermal insulation pad body is 0.15 to 12:1; (5) The length and width of the thermal insulation pad body are respectively adapted to the length and width of the thermal conductive layer; or at least one of the length and width of the thermal insulation pad body is larger than the corresponding length or width of the thermal conductive layer; (6) The composite thermal insulation pad also includes a release adhesive layer, which includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the thermal insulation pad body, and the release film is arranged on the outer surface of the adhesive layer.

19. A battery, characterized in that: Comprising the composite thermal insulation pad according to any one of claims 1 to 18.

20. The battery according to claim 19, 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.

21. The battery according to claim 20, characterized in that The composite thermal insulation pad is arranged between the large surfaces of at least two adjacent battery cells.

22. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 19 to 21.

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