Composite thermal insulation pad, battery and electric device

Abstract

The present application relates to a composite thermal insulation pad, a battery and an electric device. The composite thermal insulation pad comprises a composite phase-change layer, which comprises a phase-change material layer and a packaging layer, wherein the packaging layer is disposed on the outer peripheral side of the phase-change material layer, and a weak portion is provided on a region of the packaging layer where a packaging cavity is formed. The composite thermal insulation pad has good thermal insulation performance, is applied to a battery and has a good effect of slowing down thermal runaway of the battery.

Description

Composite thermal insulation pads, batteries and electrical devices

[0001] Related applications

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on February 8, 2024, with application number 202420290168X, entitled "Composite thermal insulation pad, battery and electrical device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] 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

[0004] With the development of new energy technologies, batteries are increasingly being used in the market, and people's requirements for battery performance are also increasing, such as the demand for energy density. However, battery cells with higher energy density have large residual energy after thermal runaway. When a battery cell thermally runs away, the heat from one battery cell will continue to transfer to adjacent battery cells, causing heat diffusion throughout the battery and causing damage to the entire battery. Therefore, how to mitigate battery thermal runaway is an urgent problem that needs to be solved.

[0005] Summary of the Invention

[0006] Based on this, it is necessary to provide a composite thermal insulation pad, battery and electrical device to solve the problem of how to prevent battery thermal runaway.

[0007] In a first aspect, the present application provides a composite thermal insulation pad, comprising:

[0008] The composite phase change layer comprises a phase change material layer and an encapsulation layer, wherein the encapsulation layer is arranged on the outer peripheral side of the phase change material layer, and a weak portion is provided on the encapsulation layer.

[0009] In the composite thermal insulation pad described above in the present application, the encapsulation layer is arranged on the outer peripheral side of the phase change material layer to form a composite phase change layer, so that the phase change material layer in the composite phase change layer is physically isolated from the outer side of the encapsulation layer, and thus before the encapsulation layer fails, the phase change material will not diffuse to the outer side of the encapsulation layer, causing the loss of the phase change material and causing contamination to the target object that needs insulation, such as a battery. In this way, the phase change material in the composite thermal insulation pad can exert better heat absorption performance, thereby achieving better thermal insulation performance; at the same time, a weak portion is provided on the area of ​​the encapsulation layer that constitutes the encapsulation cavity. Since the weak portion is located in a weak area, when the composite phase change layer absorbs more heat, the phase change material in the phase change material layer undergoes a phase change, causing the encapsulation layer to bulge. This can make the encapsulation layer break in time from the weak portion during thermal runaway, further reducing the degree of damage to the battery as a whole caused by thermal runaway. The composite thermal insulation pad described above is applied to batteries and has a good effect of slowing down battery thermal runaway.

[0010] In some embodiments, the weak portion is an area with a relatively thin thickness and / or relatively weak material strength.

[0011] In some embodiments, the weak portion is a scored area formed in the packaging layer.

[0012] In some embodiments, the phase change material layer includes a heat insulation substrate and a phase change material. The heat insulation substrate is disposed in the packaging cavity of the packaging layer, and the phase change material is filled in the heat insulation substrate.

[0013] In some embodiments, the phase change material is filled in the thermal insulation substrate in the form of phase change microcapsules, and the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material.

[0014] In some embodiments, there is a distance between at least one side edge of the thermal insulation substrate and the inner wall of the packaging cavity, and the weak portion is provided on the packaging layer and located between the edge of the thermal insulation substrate and the inner wall of the packaging cavity.

[0015] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0016] (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 mm to 7 mm;

[0017] (2) The distance between the weak portion and the inner wall of the packaging cavity is greater than 3 mm;

[0018] (3) The weak portion is linear;

[0019] (4) The extending direction of the weak portion is the same as the extending direction of the edge of the thermal insulation substrate.

[0020] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0021] (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 mm to 5 mm;

[0022] (2) The distance between the weak portion and the inner wall of the packaging cavity is 3 mm to 5 mm;

[0023] (3) The total length of the weak portion accounts for 50% to 100% of the length of the edge of the thermal insulation substrate;

[0024] (3) There are multiple weak portions, and the multiple weak portions are spaced apart along the extending direction of the edge of the thermal insulation substrate. The length of each weak portion is 1 / 20 to 1 / 10 of the length of the edge of the thermal insulation substrate.

[0025] In some embodiments, the distance between the weak portion and the edge of the thermal insulation substrate is 4 mm to 5 mm.

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

[0027] (1) The depth of the weak portion accounts for 15% to 50% of the thickness of the encapsulation layer;

[0028] (2) The weak portion is located on the outer side of the packaging layer;

[0029] (3) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film;

[0030] (4) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm;

[0031] (5) The thickness of the composite phase change layer is 1 mm to 6 mm;

[0032] (6) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer.

[0033] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0034] The packaging layer is an aluminum-plastic film, which includes an aluminum foil layer and plastic film layers arranged on both surfaces of the aluminum foil layer. The weak portion extends from the surface of the aluminum-plastic film to 30% to 60% of the thickness of the aluminum foil layer.

[0035] In some embodiments, the composite thermal insulation layer further includes an outer thermal insulation layer, which is disposed on at least one side of the outer periphery of the encapsulation layer. In this manner, the phase change material layer within the encapsulation layer can absorb heat transferred from the outer thermal insulation layer to provide thermal insulation, thereby physically isolating the phase change material layer within the composite phase change layer from the outer thermal insulation layer. Furthermore, before the encapsulation layer fails, the phase change material will not diffuse into the outer thermal insulation layer to form a heat conduction path, thereby not changing the structure and thermal insulation properties of the outer thermal insulation layer. This improves the thermal insulation properties of the composite thermal insulation pad.

[0036] In some embodiments, the composite thermal insulation pad meets at least one of the following conditions:

[0037] (1) The outer thermal insulation layer is a ceramic material layer;

[0038] (2) The thickness of the outer insulation layer is 0.5 mm to 8 mm;

[0039] (3) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is 0.15 to 12:1;

[0040] (4) The outer heat insulation layer is provided on at least one of the two sides in the thickness direction of the composite phase change layer;

[0041] (5) The length and width of the outer thermal insulation layer are respectively adapted to the length and width of the composite phase change layer; or, at least one of the length and width of the outer thermal insulation layer is larger than the corresponding length or width of the composite phase change layer.

[0042] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0043] The first thermal insulation layer and the second thermal insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first thermal insulation layer and the second thermal insulation layer.

[0044] In some embodiments, edges of the first thermal insulation layer and the second thermal insulation layer are connected to each other to form an assembly cavity, and the composite phase change layer is located in the assembly cavity.

[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 and forms at least a portion of the assembly cavity.

[0046] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

[0047] In some embodiments, the composite thermal insulation pad also includes a first packaging frame and a second packaging frame, the first packaging frame is arranged on one side of the first thermal insulation layer, and the second packaging frame is arranged on one side of the second thermal insulation layer, and the first packaging frame and the second packaging frame cooperate to fix the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer.

[0048] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is located between the first packaging frame and the second packaging frame.

[0049] In some embodiments, the first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in the limiting space formed by the first limiting groove and the second limiting groove.

[0050] In some embodiments, the outer surface of the first thermal insulation layer is flush with the outer surface of the first packaging frame, and / or the outer surface of the second thermal insulation layer is flush with the outer surface of the second packaging frame.

[0051] In some embodiments, the composite thermal insulation pad further includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

[0052] In some embodiments, the composite phase change layer further includes a heat-conducting layer disposed within the packaging layer; the heat-conducting layer is heat-conducting particles or a heat-conducting sheet.

[0053] In a second aspect, the present application provides a battery comprising any of the above-mentioned composite thermal insulation pads.

[0054] 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.

[0055] In some embodiments, the composite thermal insulation pad is disposed between the large surfaces of two adjacent battery cells.

[0056] In a third aspect, the present application provides an electrical device comprising the battery as described above.

[0057] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0059] FIG1 is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to one embodiment of the present application;

[0060] FIG2 is a schematic diagram of the front structure of the composite phase change layer of the composite thermal insulation pad shown in FIG1 ;

[0061] FIG3 is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0062] FIG4 is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0063] FIG5 is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0064] FIG6 is a schematic diagram of the three-dimensional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0065] FIG7 is a schematic cross-sectional view of the composite thermal insulation pad shown in FIG6 taken along line AA;

[0066] FIG8 is an exploded cross-sectional view of the composite thermal insulation pad shown in FIG7 ;

[0067] FIG9 is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0068] FIG10 is a stress-strain curve diagram of a composite thermal insulation pad with a weak portion at a first position according to an embodiment of the present application;

[0069] FIG11 is a stress-strain curve diagram of a composite thermal insulation pad with a weak portion at a second position according to an embodiment of the present application;

[0070] FIG12 is a stress-strain curve diagram of a composite thermal insulation pad with a weak portion at a third position according to an embodiment of the present application;

[0071] FIG13 is a schematic structural diagram of a battery according to an embodiment of the present application;

[0072] FIG14 is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0073] FIG15 is a schematic structural diagram of a battery cell in a battery according to an embodiment;

[0074] FIG16 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0075] Explanation of the accompanying drawings: 10. Composite thermal insulation pad; 11. First thermal insulation layer; 12. Second thermal insulation layer; 13. Composite phase change layer; 131. Phase change material layer; 1311. Thermal insulation substrate; 1311a. One side edge of the thermal insulation substrate; 132. Encapsulation layer; 132a. Inner wall of the encapsulation cavity; 1321. Encapsulation margin; 1322. Weak part; 141. First encapsulation frame; 142. Second encapsulation frame; 151. First adhesive layer; 152. Second adhesive layer; 16. Third thermal insulation layer; 20. Battery cell; 21. Shell; 22. Electrode assembly; 23. Cover plate; 30. Battery; 40. Electrical device. DETAILED DESCRIPTION

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0080] In this application, unless otherwise expressly specified or limited, when 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 intermediary. 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.

[0081] 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.

[0082] " 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] In order to solve the above-mentioned battery thermal runaway problem and reduce the damage and risk to the entire battery.

[0087] Referring to FIG. 1 and FIG. 2 , an embodiment of the present application provides a composite thermal insulation pad 10 , including a composite phase change layer 13 .

[0088] The composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132 . The encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 . A weak portion is provided on the area of ​​the encapsulation layer 132 that forms the encapsulation cavity.

[0089] It is understandable that the encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 and forms an encapsulation cavity, and the phase change material layer 131 is disposed in the encapsulation cavity. Further, the encapsulation cavity is a closed cavity.

[0090] In the composite thermal insulation pad 10 described above, the encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 to form a composite phase change layer 13. This physically isolates the phase change material layer 131 in the composite phase change layer 13 from the outer side of the encapsulation layer 132. Therefore, before the encapsulation layer 132 fails, the phase change material will not diffuse to the outer side of the encapsulation layer 132, causing loss of the phase change material and contamination of the target object requiring insulation, such as a battery cell. This allows the phase change material in the composite thermal insulation pad 10 to exhibit better heat absorption performance, thereby achieving better thermal insulation performance. At the same time, a weak portion 1322 is provided in the area of ​​the encapsulation layer 132 that constitutes the encapsulation cavity. Since the weak portion is located in a weak area, when the composite phase change layer 13 absorbs more heat, the phase change material in the phase change material layer 131 undergoes a phase change, causing the encapsulation layer 132 to bulge. This allows the encapsulation layer 132 to break in time from the weak portion during thermal runaway, further reducing the degree of damage to the battery as a whole due to thermal runaway. The composite thermal insulation pad 10 is applied to batteries and has a good effect of preventing thermal runaway of the batteries.

[0091] Due to the limitations of the structure, conventional technology can only use solid phase change materials as phase change materials. However, the heat absorption capacity of solid phase change materials is limited. The above-mentioned composite thermal insulation pad 10, due to its structure in which the phase change material layer 131 is arranged in the packaging cavity of the packaging layer 132, is physically isolated from the first thermal insulation layer 11 and the second thermal insulation layer 12 on both sides. Therefore, the phase change material of its phase change material layer 131 can be a solid phase change material, a liquid phase change material, or a solid-liquid mixed phase change material. Optionally, the phase change material includes but is not limited to crystalline water and salt, phase change molten salt, paraffin, silicone oil, silica-alumina sol, fatty acids, alcohols and other substances that can undergo phase change and absorb heat. It has a wider range of applications and can therefore provide better thermal insulation performance.

[0092] In addition, because the phase change material of the phase change material layer 131 will undergo phase change, for example, the solid phase change material at room temperature will turn into liquid after absorbing heat, the encapsulation layer 132 can also play the role of isolating the phase change material that is liquid after the phase change from the first insulation layer 11 and the second insulation layer 12 on both sides.

[0093] In addition, some preparation processes inevitably cause the phase change material to contain moisture. The structure in which the phase change material layer 131 is disposed in the packaging cavity of the packaging layer 132 can prevent moisture overflow from causing adverse effects on the battery.

[0094] In some embodiments, the composite phase change layer 13 further includes a heat-conducting layer disposed within the encapsulation layer 132. Furthermore, the heat-conducting layer is comprised of heat-conducting particles or a heat-conducting sheet. The heat-conducting layer disposed within the encapsulation layer 132 can, on the one hand, trigger a phase change over a larger area of ​​the phase change material layer 131, also within the encapsulation layer 132, due to its heat conduction, thereby absorbing heat and cooling the temperature. On the other hand, it can also diffuse heat to the surrounding area, further enhancing the thermal insulation effect of the composite thermal insulation pad.

[0095] Furthermore, the thermally conductive particles include, but are not limited to, metal thermally conductive particles, such as copper, aluminum, and iron thermally conductive particles. Furthermore, the thermally conductive sheet includes, but is not limited to, at least one of a metal thermally conductive sheet and a graphene thermally conductive sheet. The metal thermally conductive sheet comprises a pure metal sheet or an alloy sheet of at least one of copper, aluminum, and iron. As an example, the metal thermally conductive sheet is a copper sheet or an aluminum sheet. Furthermore, the copper sheet has a relatively good ability to suppress thermal radiation.

[0096] In some embodiments, the composite thermal insulation pad 10 further includes an outer thermal insulation layer, which is disposed on at least one side of the outer periphery of the packaging layer 132. Furthermore, the outer thermal insulation layer can be disposed on at least one side of both sides of the composite phase change layer 13 in the thickness direction.

[0097] In this way, the phase change material layer 131 in the encapsulation layer 132 can absorb the heat transferred from the outer thermal insulation layer to play a thermal insulation role, so that the phase change material layer 131 in the composite phase change layer 13 is physically isolated from the outer thermal insulation layer, and then before the encapsulation layer 132 fails, the phase change material will not diffuse into the inner part of the outer thermal insulation layer to form a heat conduction path, and will not change the structure of the outer thermal insulation layer and its thermal insulation performance, thereby improving the thermal insulation performance of the composite thermal insulation pad.

[0098] For example, the outer heat insulation layer may be provided on one side or two opposite sides of the encapsulation layer 132 in the thickness direction of the composite phase change layer 13 .

[0099] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer 11 and a second thermal insulation layer 12. The first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged on both sides of the composite phase change layer 13 in the thickness direction, so that the composite phase change layer 13 is sandwiched between the first thermal insulation layer 11 and the second thermal insulation layer 12. In other words, the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are stacked in sequence.

[0100] The above-mentioned composite thermal insulation pad 10, on the one hand, is provided with a first thermal insulation layer 11 and a second thermal insulation layer 12 at the same time, which can play a good thermal insulation role; on the other hand, the composite phase change layer 13 is provided between the first thermal insulation layer 11 and the second thermal insulation layer 12, and the composite phase change layer 13 can absorb the heat transferred from the thermal insulation layers on both sides, thereby further improving the thermal insulation performance of the above-mentioned composite thermal insulation pad 10.

[0101] It is understandable that in other examples, the outer insulation layer may include only the first insulation layer 11 or only the second insulation layer 12 , and its material and thickness may be the same or similar to those of the first insulation layer 11 or the second insulation layer 12 .

[0102] Please refer to Figure 3. In some embodiments, the composite thermal insulation pad 10 further includes an adhesive layer, and the outer thermal insulation layer is connected to the encapsulation layer 132 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 11 is connected to the encapsulation layer 132 through the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 through the second adhesive layer 152. In this way, the first thermal insulation layer 11, the composite phase change layer 13, and the second thermal insulation layer 12 of the composite thermal insulation pad 10 are connected and fixed in the thickness direction through the adhesive layer.

[0103] Furthermore, the material of the first adhesive layer 151 and the second adhesive layer 152 are each independently a silicone adhesive layer, and the thickness is independently 0.04mm to 0.06mm. 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.

[0104] 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 disposed on the outer surface of the outer thermal insulation layer (i.e., the first thermal insulation layer 11 and / or the second thermal insulation layer 12), and the release film is disposed 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 the composite thermal insulation pad 10 is simply and conveniently fixed to the target position by bonding with the third adhesive layer, thereby fixing the composite thermal insulation pad 10.

[0105] As an example, the aforementioned release adhesive layer is provided on the outer surfaces of the first insulation layer 11 and the second insulation layer 12 of the composite thermal insulation mat 10. During use, the composite thermal insulation mat 10 can be bonded and fixed to two objects, for example, two adjacent battery cells, using the release adhesive layers on both sides, so that the composite thermal insulation mat 10 is positioned between the two adjacent battery cells.

[0106] As shown in FIG. 2 , the first thermal insulation layer 11 and the second thermal insulation layer 12 are physically separated by the composite phase change layer 13 . In other words, the edges between the first thermal insulation layer 11 and the second thermal insulation layer 12 are not connected to each other.

[0107] In some embodiments, the length and width of the outer thermal insulation layer are respectively adapted to the length and width of the composite phase change layer 13. In other embodiments, at least one of the length and width of the outer thermal insulation layer is greater than the corresponding length or width of the composite phase change layer 13.

[0108] Referring to Figure 4 , in some embodiments, the edges of the first and second insulation layers 11, 12 are interconnected to form an assembly cavity, within which the composite phase change layer 13 is located. This structural arrangement allows the composite phase change layer 13 to be positioned within the first and second insulation layers 11, 12, reducing the risk of the composite phase change layer 13 falling off and also reducing the risk of leakage when using liquid phase change materials.

[0109] Furthermore, the edge of at least one side surface of at least one of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portion encloses at least part of the assembly cavity. As an example, the edge of at least one side surface of both the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portions of the two are arranged relative to each other and enclose the assembly cavity. In the specific example shown in Figure 4, the edges of the four sides of the surface of one side of the first thermal insulation layer 11 and the second thermal insulation layer 12 form a convex portion, and the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged relative to each other and enclose the assembly cavity.

[0110] Typically, both sides of phase-change material layer 131 are encapsulated with an encapsulation film, leaving an encapsulation margin on its sides, such as encapsulation margin 1321 shown in FIG8 . That is, encapsulation layer 132 has an encapsulation margin. When composite phase-change layer 13 is disposed within first and second insulation layers 11, 12, the encapsulation margin is folded and positioned within the assembly cavity.

[0111] As an example, the encapsulation layer 132 has an encapsulation margin on all four sides.

[0112] Referring to Figure 5, in some embodiments, the composite thermal insulation pad 10 further includes a third thermal insulation layer 16, and a composite phase change layer 13 is also provided between the second thermal insulation layer 12 and the third thermal insulation layer 16. Furthermore, the composite thermal insulation pad 10 may further include more thermal insulation layers, and the composite phase change layer 13 may also be provided between the adjacent thermal insulation layers.

[0113] Furthermore, the selection range of materials and thicknesses of the third thermal insulation layer 16 and other thermal insulation layers can be the same as that of the first thermal insulation layer 11 and the second thermal insulation layer 12; the specific materials and specific thicknesses can be the same or different.

[0114] Please refer to Figures 6 and 7. In some embodiments, the composite thermal insulation pad 10 also includes a first packaging frame 141 and a second packaging frame 142. The first packaging frame 141 is arranged on one side of the first thermal insulation layer 11, and the second packaging frame 142 is arranged on one side of the second thermal insulation layer 12. The first packaging frame 141 and the second packaging frame 142 cooperate to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12.

[0115] Furthermore, the first packaging frame 141 and the second packaging frame 142 are each independently a rubber frame or a silicone frame. In other words, the first packaging frame 141 and the second packaging frame 142 are each independently made of rubber or silicone. Furthermore, the first packaging frame 141 and the second packaging frame 142 are both rectangular frame structures, such as a square frame, and specifically can be a silicone square frame.

[0116] In the example shown in Figures 7 and 8, 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 11, the composite phase change layer 13 and the second thermal insulation layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can limit the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 in the thickness direction and the radial direction of the composite thermal insulation pad 10, thereby improving the structural stability of the composite thermal insulation pad 10. Among them, the radial direction of the composite thermal insulation pad 10 refers to the direction from the center of the composite thermal insulation pad 10 to the edge of the composite thermal insulation pad 10. Further, at this time, the packaging margin 1321 of the packaging layer 132 can be located between the first packaging frame 141 and the second packaging frame 142. As shown in Figure 7, the packaging margin 1321 is pressed in the middle by the first packaging frame 141 and the second packaging frame 142.

[0117] It can be understood that when the above-mentioned first packaging frame 141 and second packaging frame 142 and the above-mentioned first thermal insulation layer 11 and second thermal insulation layer 12 that can form an assembly cavity are provided at the same time, the packaging margin portion 1321 of the packaging layer 132 can pass through between the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 and be located between the first packaging frame 141 and the second packaging frame 142, or the packaging margin portion 1321 of the packaging layer 132 can also be folded and located in the assembly cavity.

[0118] Referring to Figure 9 , in other embodiments, the outer surface of the first thermal insulation layer 11 is flush with the outer surface of the first packaging frame 141, and / or the outer surface of the second thermal insulation layer 12 is flush with the outer surface of the second packaging frame 142. This can minimize the thickness of the composite thermal insulation pad 10 and reduce the space it occupies while providing better thermal insulation performance.

[0119] As an example, based on the aforementioned first adhesive layer 151 and second adhesive layer 152, the aforementioned first packaging frame 141 and second packaging frame 142 can be further used to secure the first thermal insulation layer 11, the composite phase change layer 13, and the second thermal insulation layer 12 around their perimeters, thereby improving the structural stability of the composite thermal insulation pad 10. Furthermore, in this case, there is no need for the packaging frame to secure the thickness direction, so that the outer surface of the first thermal insulation layer 11 can be flush with the outer surface of the first packaging frame 141, and the outer surface of the second thermal insulation layer 12 can be flush with the outer surface of the second packaging frame 142.

[0120] It can be understood that in some embodiments, the first thermal insulation layer 11, the composite phase change layer 13, the second thermal insulation layer 12, and the third thermal insulation layer 16 can be connected by the above-mentioned adhesive layer, or by the above-mentioned packaging frame, or by both the above-mentioned adhesive layer and the packaging frame, or by neither, for example, the first thermal insulation layer 11 can be directly formed on the packaging layer 132 of the composite phase change layer 13.

[0121] Furthermore, the first thermal insulation layer 11 , the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently include at least one of thermal insulation felt and thermal insulation coating.

[0122] Furthermore, when any of the aforementioned thermal insulation layers includes both a thermal insulation felt and a thermal insulation coating, the thermal insulation coating may be optionally disposed on a side closer to the composite phase change layer 13. Specifically, the thermal insulation coating is disposed on the surface of the encapsulation layer 132 of the composite phase change layer 13, and the thermal insulation felt is disposed on a side further away from the composite phase change layer 13. In other words, the thermal insulation coating is formed directly on the surface of the encapsulation layer 132 and is located between the encapsulation layer 132 and the thermal insulation felt.

[0123] For example, in the examples of Figures 1, 3 and 5, the first thermal insulation layer 11 and the second thermal insulation layer 12 are thermal insulation felt, and the third thermal insulation layer 16 is also thermal insulation felt. In other examples, the first thermal insulation layer 11 and the second thermal insulation layer 12 may also be thermal insulation coatings. In comparison, the thickness of the thermal insulation coating is thinner, and the overall thickness of the composite thermal insulation pad obtained is thinner, and the required space is relatively smaller. The thermal insulation layer of the composite thermal insulation pad 10 can optionally adopt a thermal insulation coating, or a composite of a thermal insulation coating and ceramic felt, which can take into account both a smaller occupied space and better thermal insulation performance.

[0124] For example, in the example shown in FIG4 , the first insulation layer 11 and the second insulation layer 12 are insulation felts, and the assembly cavity thereon can be integrally formed when the insulation felt is formed, or can be formed by grooving after the insulation felt is formed.

[0125] It is understood that the thermal insulation felt can be connected to the composite phase change layer 13 via the aforementioned adhesive layer or encapsulation frame. The thermal insulation coating can be formed directly on the encapsulation layer 132 in the composite phase change layer 13. As an example, the thermal insulation coating can be formed by coating the encapsulation layer 132 of the composite phase change layer 13 with a slurry and then drying it to form a coating.

[0126] In some embodiments, the outer insulation layer is a ceramic material layer.

[0127] Furthermore, the thermal insulation felt may be a ceramic thermal insulation felt; furthermore, the thermal insulation coating may be a ceramic thermal insulation coating. It is understood that both the ceramic thermal insulation felt and the ceramic thermal insulation coating are ceramic material layers. In some embodiments, the outer thermal insulation layer is a ceramic material layer. In other words, the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 16 described above are each independently a ceramic material layer.

[0128] The material of the "ceramic material layer" in this application includes, but is not limited to, at least one of ceramic oxides, ceramic nitrides, and ceramic carbides. Among them, ceramic oxides include, but are not limited to, at least one of silicon oxide and aluminum oxide; ceramic nitrides include, but are not limited to, at least one of silicon nitride and boron nitride; and ceramic carbides include, but are not limited to, silicon carbide.

[0129] 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.

[0130] 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.

[0131] In some embodiments, the first thermal insulation layer 11, the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently have a thermal conductivity of ≤0.020 W / m·K at 25°C, a thermal conductivity of ≤0.027 W / m·K at 200°C, a thermal conductivity of ≤0.035 W / m·K at 300°C, and a thermal conductivity of ≤0.080 W / m·K at 500°C.

[0132] In some embodiments, the density of the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 16 is independently 0.2 g / cm 3 ~0.22g / cm 3 .

[0133] In some embodiments, the thickness ratio of the composite phase change layer 13 to the outer heat insulation layer 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.

[0134] Furthermore, the thickness of the outer heat insulation layer is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm; it can be optionally 1 mm to 8 mm.

[0135] 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.

[0136] In some embodiments, the thickness of the first thermal insulation layer 11 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.

[0137] In some embodiments, the thickness of the second thermal insulation layer 12 is 0.5 mm to 8 mm, and as examples, may be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm.

[0138] Furthermore, the thickness of the second heat insulation layer 12 is 0.5 mm to 8 mm, and as an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm.

[0139] In some embodiments, the thickness of the composite phase change layer 13 is 1 mm to 6 mm, and can be 1 mm to 4 mm. For example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, or 6 mm. It can also be 1.5 mm to 3.5 mm.

[0140] In some embodiments, the thickness of the encapsulation layer 132 is 0.1 mm to 0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and optionally 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0141] In some embodiments, the packaging layer 132 is an aluminum-plastic film or a polymer packaging film. Further, the polymer packaging film can be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0142] It can be understood that the weak portion 1322 on the encapsulation layer 132 is a relatively weak area on the encapsulation layer 132 .

[0143] In some embodiments, the weak portion 1322 is a region of relatively thin thickness and / or relatively weak material strength. In other words, the weak portion 1322 can be a region of relatively thin thickness but constant material strength, which can be formed by locally thinning the encapsulation layer 132. The weak portion 1322 can also be a region of relatively constant thickness but relatively weak material strength, which can be formed by locally weakening the material strength of the encapsulation layer 132, for example, by using materials of different strengths. Alternatively, the weak portion 1322 can be a region of relatively thin thickness and relatively weak material strength. It should be understood that the material strength here refers to the strength of the material itself.

[0144] Furthermore, the weak portion 1322 is a notch area formed on the encapsulation layer 132. It can be understood that the notch area is formed by thinning the surface of the encapsulation layer 132 by embossing, and the thickness of the notch area is relatively thin.

[0145] Furthermore, the weak portion 1322 can be disposed on the outside or inside of the encapsulation layer 132. The outside refers to the surface of the encapsulation layer 132 away from the phase change material layer 131, and the inside refers to the surface of the encapsulation layer 132 close to the phase change material layer 131.

[0146] Furthermore, the depth of the weak portion 1322 accounts for 15% to 50% of the thickness of the encapsulation layer 132, for example, 15%, 20%, 30%, 35%, 40%, 45%, or 50%. Controlling this thickness ratio allows the encapsulation layer 132 to provide both good isolation when no package breakage is required and good timely package breakage in the event of thermal runaway.

[0147] Furthermore, the aluminum-plastic film includes an aluminum foil layer and plastic film layers arranged on both surfaces of the aluminum foil layer.

[0148] Furthermore, when encapsulation layer 132 is an aluminum-plastic film, the weak portion extends from the surface of the aluminum-plastic film to 30% to 60% of the thickness of the aluminum foil layer, for example, 30%, 40%, 50%, or 60%. The weak portion is controlled to penetrate the aluminum foil layer without penetrating the aluminum foil layer, and is further controlled to penetrate 30% to 60% of the thickness of the aluminum foil layer. This ensures that encapsulation layer 132 provides both better isolation when rupture is not necessary and better, more timely rupture in the event of thermal runaway.

[0149] 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.

[0150] In some examples, encapsulation layer 132 includes a polypropylene layer, an aluminum foil layer, a nylon layer, and a polyester layer stacked from inside to outside. Specifically, the thicknesses of the polypropylene layer, the aluminum foil layer, the nylon layer, and the polyester layer are 80 μm, 40 μm, 15 μm, and 6 μm, respectively. The weak portion 1322 may extend from one side of the polyester layer to half the thickness of the aluminum foil layer.

[0151] In some embodiments, the phase change material layer 131 includes a thermal insulation substrate 1311 (as shown in FIG2 ) and a phase change material, and the phase change material is filled in the thermal insulation substrate 1311. In other words, the pores of the thermal insulation substrate are filled with the phase change material.

[0152] Furthermore, the thermal insulation substrate 1311 may be a ceramic material substrate, such as ceramic fiber felt.

[0153] Furthermore, in some examples, at least a portion of the phase change material is directly filled in the pores of the thermal insulation substrate 1311. In other examples, at least a portion of the phase change material can also be filled in the pores of the thermal insulation substrate 1311 in the form of phase change microcapsules. It is understood that the same thermal insulation substrate 1311 can also include two states of phase change material: one in which the phase change material is directly filled in the pores of the thermal insulation substrate 1311, and the other in which the phase change material is filled in the pores of the thermal insulation substrate 1311 in the form of phase change microcapsules.

[0154] It is understood that the phase change material layer 131 can be obtained by soaking a porous thermal insulation substrate 1311, such as ceramic fiber felt, in a liquid phase change material, for example, by soaking it in a molten phase change material and then cooling it, or by soaking it in a phase change material solution and then drying or heat-insulating it. In addition to absorbing heat, the phase change material layer 131 also provides thermal insulation. When the phase change material vaporizes and breaks through the encapsulation layer 132, that is, the composite thermal insulation pad 10 fails, the thermal insulation substrate 1311 in the phase change material layer 131 can continue to provide thermal insulation. In other words, the phase change material directly fills the pores of the thermal insulation substrate 1311.

[0155] In other embodiments, the phase change material is filled in the pores of the thermal insulation substrate 1311 in the form of phase change microcapsules. In other words, the pores of the thermal insulation substrate 1311 of the phase change material layer 131 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, wherein the wall material wraps 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 1311 can also be directly filled with both the phase change material and the aforementioned phase change microcapsules.

[0156] The above-mentioned phase change material layer 131 can be obtained by dispersing phase change microcapsules in a solvent to obtain a phase change microcapsule dispersion, then immersing the thermal insulation substrate 1311 in the phase change microcapsule dispersion, allowing the phase change microcapsules to fill the pores of the thermal insulation substrate 1311, and removing the solvent in the phase change microcapsule dispersion.

[0157] In this way, the phase change microcapsules in the phase change material layer 131 absorb heat. When the battery cell thermally runs away, the phase change material in the adjacent composite thermal insulation pad 10 vaporizes and breaks the packaging layer 132, that is, the composite thermal insulation pad 10 fails. At this time, the thermal insulation substrate 1311 in the phase change material layer 131 can continue to play a thermal insulation role.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] Furthermore, the phase-change microcapsules have a Dv50 particle size of 5 μm to 8 μm. The Dv50 particle size, also known as the volume average particle size (Dv50), represents the particle size corresponding to 50% of the cumulative volume distribution of the particles. This can be measured using methods known in the art, for example, using a laser particle size analyzer (e.g., Malvern Master Size 3000).

[0162] Furthermore, the thermal conductivity of the wall material at 25° C. is ≥0.32 W / mK. Such a wall material has a good thermal conductivity and can better conduct heat to the phase change material inside it.

[0163] 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.

[0164] The material selection of the above-mentioned thermal insulation substrate 1311 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 1311 is a ceramic fiber mat. The ceramic fiber mat has ceramic fibers 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.

[0165] 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, silicon dioxide particles, and the like.

[0166] 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 and oil phases and stirring to form a Pickering emulsion; adding the raw materials required to prepare the polymer matrix of the wall material (such as a water-soluble polymer monomer or prepolymer aqueous solution) to the Pickering emulsion; and stirring and polymerizing at room temperature to form a water-insoluble condensation polymer (i.e., the polymer matrix) with a cross-linked three-dimensional network structure at the emulsion interface.

[0167] The polymer matrix of the above-mentioned material has better compatibility with phase change materials such as paraffin wax, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of the phase change microcapsules.

[0168] The polymer matrix of the above material has better compatibility with paraffin wax, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of the phase change microcapsules.

[0169] It is understood that the phase-change material layer 131 includes the aforementioned thermal insulation substrate 1311 and the phase-change material filling the pores of the thermal insulation substrate 1311. The phase-change material layer 131 is located within the packaging cavity. In other words, the thermal insulation substrate 1311 is also located within the packaging cavity. Further, referring to FIG. 2 , at least one side edge 1311a of the thermal insulation substrate 1311 located within the packaging cavity is spaced apart from the inner wall 132a of the packaging cavity. A weak portion 1322 is provided on the packaging layer 132 and is located between the edge 1311a of the thermal insulation substrate 1311 and the inner wall 132a of the packaging cavity.

[0170] It can be understood that since the encapsulation layer 132 is provided on the outer surface of the phase change material layer 131 and forms an encapsulation cavity, the encapsulation layer 132 includes a first region in contact with the first thermal insulation layer 11, a second region in contact with the second thermal insulation layer 12, and a third region connecting the first and second regions. The weak portion 1322 is provided in the first and / or second regions of the encapsulation layer 132 and is located between the edge 1311a of the thermal insulation substrate 1311 and the inner wall 132a of the encapsulation cavity, that is, located in the region of the encapsulation layer 132 forming the aforementioned gap. The inner wall 32a of the encapsulation cavity herein refers to the inner wall of the encapsulation cavity directly opposite the side edge 1311a of the thermal insulation substrate 1311, that is, the third region directly opposite the side edge 1311a of the thermal insulation substrate 1311.

[0171] Furthermore, the two opposite surfaces of the thermal insulation substrate 1311 are bonded to the opposite inner walls of the encapsulation layer, that is, the two opposite surfaces of the thermal insulation substrate 1311 are bonded to the first area and the second area of ​​the encapsulation layer 132 respectively. The side edge of the thermal insulation substrate 1311 is the edge connecting the two opposite surfaces of the thermal insulation substrate 1311. The thermal insulation substrate 1311 is square, and there is a gap between the side edges on all sides and the inner walls on all sides of the encapsulation cavity. In other words, the above-mentioned gap surrounds the four edges of the thermal insulation substrate 1311. Reserving this gap can, on the one hand, prevent the stress between the four edges of the thermal insulation substrate 1311 and the encapsulation layer from being too great to cause damage to the encapsulation layer 132, and on the other hand, reserve a certain volume change space for the phase change material therein.

[0172] Furthermore, the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is controlled to be 2 mm to 7 mm, optionally 2 mm to 5 mm, and more preferably 4 mm to 5 mm. When other conditions remain unchanged, the magnitude of the bag-breaking force is related to the distance between the weak portion and the edge of the thermal insulation substrate 1311.

[0173] As shown in Figures 10 to 12, stress-strain curves of composite thermal insulation pads at different locations of weak parts are shown. The horizontal axis is strain, which is the compression rate in %, and the vertical axis is strain in MPa. The stress-strain test method is as follows: Use a press to compress the sample to a certain pressure at a compression rate of 2mm / min under an inlet stress of 0.008MPa, and record the compression stress-strain curve. The test is carried out in an environment with a temperature of 23℃±5℃, a relative humidity of 45% to 75%, and an atmospheric pressure of 86kPa to 106kPa. As the pressure of the press increases, the strain (compression rate) of the composite thermal insulation pad increases, and the pressure on the composite thermal insulation pad increases. When the compression rate reaches a certain value, the encapsulation layer in the composite thermal insulation pad breaks, and the pressure on the composite thermal insulation pad decreases rapidly. The stress corresponding to the inflection point where the pressure decreases rapidly is recorded, which is the breaking force of the composite thermal insulation pad.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] Furthermore, in a specific example, as shown in Figure 10, when other conditions remain unchanged, when the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is 2mm~3mm, the bag-breaking force is 0.28Mpa; as shown in Figure 11, when the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is 4mm~5mm, the bag-breaking force is 0.38Mpa; as shown in Figure 12, when the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is 6mm~7mm, the bag-breaking force is 1.69Mpa.

[0178] Optionally, in order to enable the packaging layer 132 to break more quickly and promptly in the event of thermal runaway and discharge gas, the distance h1 between the weak portion 1322 and the edge 1311 a of the thermal insulation substrate 1311 is controlled to be 4-5 mm.

[0179] Furthermore, the distance h2 between the weak portion 1322 and the inner wall 132a of the packaging cavity is greater than 3 mm, and can be selected from 3 mm to 5 mm; to prevent the weak portion 1322 from being too close to the edge of the packaging layer 132 and affecting the packaging strength of the packaging layer 132.

[0180] Furthermore, the weak portion 1322 is linear. Furthermore, the extension direction of the weak portion 1322 is the same as the extension direction of the edge 1311a of the thermal insulation substrate 1311. It is understood that in other examples, the weak portion 1322 may also be arc-shaped, etc., and is not limited thereto.

[0181] Furthermore, the total length of the weak portion 1322 accounts for 50% to 100% of the length of the edge of the thermal insulation substrate 1311, and can be 50% to 80%. For example, the length ratio can be 50%, 60%, 70%, 80%, 90%, or 100%. The total length ratio of the weak portion 1322 is controlled to ensure that thermal runaway occurs and the package is broken in a timely manner.

[0182] Furthermore, there are multiple weak portions 1322, which are spaced apart along the extending direction of the edge 1311a of the thermal insulation substrate 1311. The length of each weak portion 1322 is 1 / 20 to 1 / 10 of the edge 1311a of the thermal insulation substrate 1311, for example, 1 / 20, 1 / 15, or 1 / 10.

[0183] In a specific example, the weak portion 1322 is a notched area, and the length of the weak portion 1322 is 5 mm to 20 mm, and the width of the weak portion 1322 is 0.5 mm to 2 mm.

[0184] Referring to FIG. 13 and FIG. 14 , another embodiment of the present application further provides a battery 30 , which includes a plurality of battery cells 20 and any of the above-mentioned composite thermal insulation pads 10 , wherein the composite thermal insulation pad 10 is disposed between at least two adjacent battery cells 20 .

[0185] 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 undergoes thermal runaway, the heat is transferred to the adjacent (for example, adjacent) composite thermal insulation pad 10, and the phase change material layer 131 in the composite thermal insulation pad 10 absorbs heat, thereby preventing the battery from thermal runaway. In the second stage, the phase change material layer 131 absorbs heat until a phase change occurs, absorbing a large amount of heat. In the third stage, the encapsulation layer 132 and the phase change material layer 131 fail: the phase change material in the phase change material layer 131 is converted into gas and breaks the encapsulation layer 132, discharging the high-temperature gas. In the fourth stage, the first thermal insulation layer 11 and the second thermal insulation layer 12 and the optional thermal insulation substrate in the composite phase change layer 13 continue to play a role in thermal insulation.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] Furthermore, the composite thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0190] 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.

[0191] 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.

[0192] For example, Figure 15 is a square-structured battery cell 20 as an example. The battery cell 20 includes a shell 21, a cover plate 23 and an electrode assembly 22. The electrode assembly 22 is accommodated in the shell 21. The shell 21 is provided with an opening, and the cover plate 23 is sealed in the opening. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the negative electrode sheet and the separator can be formed by a winding process or a lamination process. Furthermore, the electrode assembly 22 also includes an electrolyte, such as an electrolyte. The electrolyte is impregnated in the electrode assembly 22. The number of electrode assemblies 22 contained in the battery cell 20 can be one or more, and those skilled in the art can select according to specific actual needs.

[0193] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0194] 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.

[0195] 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.

[0196] As a further non-limiting example, the wall thickness of the housing 21 is 0.5 mm to 0.8 mm.

[0197] Furthermore, the housing 21 is an aluminum alloy housing; for example, a third-series aluminum alloy housing or a fifth-series aluminum alloy housing.

[0198] 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%.

[0199] 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%.

[0200] 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.

[0201] Figure 16 shows an example of an electric device 40. The electric device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the electric device's requirements for high power and high energy density of secondary batteries, a battery pack or battery module can be used.

[0202] 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.

[0203] 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.

[0204] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A composite thermal insulation pad, comprising: The composite phase change layer comprises a phase change material layer and an encapsulation layer. The encapsulation layer is arranged on the outer peripheral side of the phase change material layer. A weak portion is provided on the area of the encapsulation layer forming the encapsulation cavity.

2. The composite thermal insulation pad according to claim 1, wherein: The weak portion is an area with a relatively thin thickness and / or relatively weak material strength.

3. The composite thermal insulation pad according to any one of claims 1 to 2, wherein: The weak portion is a scoring area formed in the packaging layer.

4. The composite thermal insulation pad according to any one of claims 1 to 3, wherein: The phase change material layer includes a heat insulation substrate and a phase change material. The heat insulation substrate is arranged in the packaging cavity of the packaging layer, and the phase change material is filled in the heat insulation substrate.

5. The composite thermal insulation pad according to claim 4, wherein: The phase change material is filled in the heat insulation substrate in the form of phase change microcapsules. The phase change microcapsules include a core material and a wall material. The wall material wraps around the outer surface of the core material, and the core material includes the phase change material.

6. The composite thermal insulation pad according to claim 4, wherein: There is a distance between at least one side edge of the heat insulation substrate and the inner wall of the packaging cavity. The weak portion is provided on the packaging layer and is located between the edge of the heat insulation substrate and the inner wall of the packaging cavity.

7. The composite thermal insulation pad according to claim 5, wherein: The composite thermal insulation pad meets at least one of the following conditions: (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 mm to 7 mm; (2) The distance between the weak portion and the inner wall of the packaging cavity is greater than 3 mm; (3) The weak portion is linear; (4) The extending direction of the weak portion is the same as the extending direction of the edge of the thermal insulation substrate.

8. The composite thermal insulation pad according to claim 7, wherein: The composite thermal insulation pad meets at least one of the following conditions: (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 mm to 5 mm; (2) The distance between the weak portion and the inner wall of the packaging cavity is 3 mm to 5 mm; (3) The total length of the weak portion accounts for 50% to 100% of the length of the edge of the thermal insulation substrate; (3) There are multiple weak portions, and the multiple weak portions are spaced apart along the extending direction of the edge of the thermal insulation substrate. The length of each weak portion is 1 / 20 to 1 / 10 of the length of the edge of the thermal insulation substrate.

9. The composite thermal insulation pad according to claim 8, wherein: The distance between the weak portion and the edge of the heat insulation substrate is 4 mm to 5 mm.

10. The composite thermal insulation pad according to any one of claims 1 to 9, wherein: The composite thermal insulation pad meets at least one of the following conditions: (1) The depth of the weak portion accounts for 15% to 50% of the thickness of the encapsulation layer; (2) The weak portion is located on the outer side of the packaging layer; (3) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film; (4) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm; (5) The thickness of the composite phase change layer is 1 mm to 6 mm; (6) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer.

11. The composite thermal insulation pad according to any one of claims 1 to 10, wherein: The composite thermal insulation pad meets at least one of the following conditions: The packaging layer is an aluminum-plastic film, which includes an aluminum foil layer and plastic film layers arranged on both surfaces of the aluminum foil layer. The weak portion extends from the surface of the aluminum-plastic film to 30% to 60% of the thickness of the aluminum foil layer.

12. The composite thermal insulation pad according to any one of claims 1 to 11, wherein: The composite heat-insulating layer further includes an outer heat-insulating layer, and the outer heat-insulating layer is arranged on at least one side of the outer periphery of the packaging layer.

13. The composite thermal insulation pad according to claim 12, wherein: The composite thermal insulation pad meets at least one of the following conditions: (1) The outer thermal insulation layer is a ceramic material layer; (2) The thickness of the outer insulation layer is 0.5 mm to 8 mm; (3) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is 0.15 to 12:1; (4) The outer heat insulation layer is provided on at least one of the two sides in the thickness direction of the composite phase change layer; (5) The length and width of the outer thermal insulation layer are respectively adapted to the length and width of the composite phase change layer; or, at least one of the length and width of the outer thermal insulation layer is larger than the corresponding length or width of the composite phase change layer.

14. The composite thermal insulation pad according to claim 12, wherein: The outer heat insulation layer includes a first heat insulation layer and a second heat insulation layer; The first thermal insulation layer and the second thermal insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first thermal insulation layer and the second thermal insulation layer.

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

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

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

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

19. The composite thermal insulation pad according to claim 18, wherein: The packaging layer has a packaging margin portion, and the packaging margin portion is located between the first packaging frame and the second packaging frame.

20. The composite thermal insulation pad according to claim 18, wherein: The first packaging frame has a first limiting groove, the second packaging frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in a limiting space formed by the first limiting groove and the second limiting groove.

21. The composite thermal insulation pad according to claim 18, wherein: One or more of the following conditions are met: (1) The outer surface of the first thermal insulation layer is flush with the outer surface of the first packaging frame; (2) The outer surface of the second heat insulation layer is flush with the outer surface of the second packaging frame.

22. The composite thermal insulation pad according to any one of claims 14 to 21, wherein: The composite thermal insulation pad also includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

23. The composite thermal insulation pad according to any one of claims 1 to 22, wherein: The composite phase change layer further includes a heat conducting layer arranged in the packaging layer; the heat conducting layer is heat conducting particles or heat conducting sheets.

24. A battery comprising the composite thermal insulation pad according to any one of claims 1 to 23.

25. The battery of claim 24, wherein It also includes a plurality of battery cells, and the composite thermal insulation pad is arranged between at least two adjacent battery cells.

26. The battery according to claim 25, wherein The composite thermal insulation pad is arranged between the large surfaces of two adjacent battery cells.

27. An electrical device comprising the battery according to any one of claims 24 to 26.

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