Composite heat insulation pad, battery and electric device

Abstract

The utility model relates to a composite heat insulation pad, a battery and an electric device. The composite heat insulation pad comprises a composite phase change layer, the composite phase change layer comprises a phase change material layer and a packaging layer, the packaging layer is arranged on the peripheral side of the phase change material layer, and a weak part is arranged on the area, forming a packaging cavity, of the packaging layer. The composite heat insulation pad has good heat insulation performance, is applied to a battery, and has a good effect of preventing and slowing the thermal runaway of the battery.

Description

Technical Field

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

[0002] With the development of new energy technologies, batteries are being used more and more widely in the market, and people are demanding higher and higher performance from batteries, such as higher energy density. However, battery cells with higher energy density have large residual energy after thermal runaway. When one of the battery cells goes into thermal runaway, its heat will continue to transfer from one battery cell to the adjacent battery cell, thus causing heat diffusion of the entire battery, causing damage to the entire battery. Therefore, how to slow down battery thermal runaway is an urgent problem to be solved. Utility Model Content

[0003] Based on this, it is necessary to provide a composite thermal insulation pad, battery and electrical device to address the problem of how to mitigate battery thermal runaway.

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

[0005] The composite phase change layer comprises a phase change material layer and a packaging layer, wherein the packaging layer is arranged on the outer peripheral side of the phase change material layer, and a weak portion is arranged on the packaging layer.

[0006] The composite thermal insulation pad mentioned above in the present application has an encapsulation layer arranged on the outer 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 then 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, and thus have better thermal insulation performance; at the same time, a weak part is provided on the area of ​​the encapsulation layer that constitutes the encapsulation cavity. Since the weak part 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, which can make the encapsulation layer break in time from the weak part during thermal runaway, further reducing the degree of damage to the battery as a whole due to thermal runaway. The composite thermal insulation pad is applied to batteries, and has a good effect of slowing down thermal runaway of batteries.

[0007] In some embodiments, the weak portion is a region with a relatively thin thickness and / or a relatively weak material strength.

[0008] In some embodiments, the weak portion is a notch region formed in the packaging layer.

[0009] 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.

[0010] In some embodiments, the phase change material is filled in the thermal insulation substrate in the form of phase change microcapsules, the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material.

[0011] 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.

[0012] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0013] (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 to 7 mm;

[0014] (2) The distance between the weak portion and the inner wall of the packaging cavity is greater than 3 mm;

[0015] (3) The weak portion is linear;

[0016] (4) The extending direction of the weak portion is the same as the extending direction of the edge of the thermal insulation substrate.

[0017] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0018] (1) The distance between the weak portion and the edge of the thermal insulation substrate is 2 to 5 mm;

[0019] (2) The distance between the weak portion and the inner wall of the packaging cavity is 3-5 mm;

[0020] (3) The total length of the weak portion accounts for 50% to 100% of the length of the edge of the thermal insulation substrate;

[0021] (3) There are a plurality of the weak portions, and the plurality of the weak portions are arranged at intervals along the extension direction of the edge of the thermal insulation substrate, and the length of each of the weak portions is 1 / 20 to 1 / 10 of the length of the edge of the thermal insulation substrate.

[0022] In some embodiments, the distance between the weak portion and the edge of the thermal insulation substrate is 4-5 mm.

[0023] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0024] (1) The depth of the weak portion accounts for 15% to 50% of the thickness of the encapsulation layer;

[0025] (2) The weak portion is disposed on the outer side of the packaging layer;

[0026] (3) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film;

[0027] (4) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm;

[0028] (5) The thickness of the composite phase change layer is 1 mm to 6 mm;

[0029] (6) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer.

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

[0031] The encapsulation 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 penetrates from the surface of the aluminum-plastic film to 30% to 60% of the thickness of the aluminum foil layer.

[0032] In some embodiments, the composite thermal insulation layer further includes an outer thermal insulation layer, and the outer thermal insulation layer is disposed on at least one side of the outer peripheral side of the encapsulation layer. In this way, the phase change material layer in the encapsulation layer can absorb the heat transferred from the outer thermal insulation layer to play a role in thermal insulation, so that the phase change material layer in the composite phase change layer is physically isolated from the outer thermal insulation layer, and then before the encapsulation layer fails, the phase change material will not diffuse into the outer thermal insulation layer to form a heat conduction path, and then will not change the structure of the outer thermal insulation layer and its thermal insulation performance, so that the thermal insulation performance of the composite thermal insulation pad can be improved.

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

[0034] (1) The outer insulation layer is a ceramic material layer;

[0035] (2) The thickness of the outer insulation layer is 0.5 mm to 8 mm;

[0036] (3) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is 0.15-12:1;

[0037] (4) The outer heat insulation layer is disposed on at least one of the two sides in the thickness direction of the composite phase change layer;

[0038] (5) The length and width of the outer heat 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 heat insulation layer is larger than the corresponding length or width of the composite phase change layer.

[0039] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0040] The first heat insulation layer and the second heat 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 heat insulation layer and the second heat insulation layer.

[0041] 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.

[0042] 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.

[0043] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

[0044] 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.

[0045] 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.

[0046] 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 a limiting space formed by the first limiting groove and the second limiting groove.

[0047] In some embodiments, the outer surface of the first heat insulation layer is flush with the outer surface of the first packaging frame, and / or the outer surface of the second heat insulation layer is flush with the outer surface of the second packaging frame.

[0048] In some embodiments, 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.

[0049] In some embodiments, the composite phase change layer further includes a heat-conducting layer disposed in the packaging layer; the heat-conducting layer is heat-conducting particles or heat-conducting sheets.

[0050] In a second aspect, the present application provides a battery comprising any of the above-mentioned composite thermal insulation pads.

[0051] In some of the embodiments, a plurality of battery cells are further included, and the composite thermal insulation pad is disposed between at least two adjacent battery cells.

[0052] In some of the embodiments, the composite thermal insulation pad is disposed between the large surfaces of two adjacent battery cells.

[0053] In a third aspect, the present application provides an electrical device, comprising the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] 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;

[0055] Figure 2 for Figure 1 A schematic diagram of the front structure of the composite phase change layer of the composite thermal insulation pad shown;

[0056] Figure 3 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0057] Figure 4 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0058] Figure 5 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0059] Figure 6 This is a schematic diagram of the three-dimensional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0060] Figure 7 for Figure 6 A schematic cross-sectional view of the composite thermal insulation pad shown in FIG.

[0061] Figure 8 for Figure 7 An exploded cross-sectional view of the composite thermal insulation pad shown;

[0062] Fig. 9 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0063] Fig.10 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;

[0064] Fig.11 A stress-strain curve diagram of a composite thermal insulation pad at a second position of a weak portion according to an embodiment of the present application;

[0065] Fig.12 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;

[0066] Fig.13 This is a schematic diagram of the structure of a battery according to one embodiment of the present application;

[0067] Fig.14 This is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0068] Fig.15 is a schematic structural diagram of a battery cell in a battery according to an embodiment;

[0069] Fig.16 A schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0070] Description of reference numerals:

[0071] 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 thermal insulation substrate; 132. Packaging layer; 132a. Inner wall of packaging cavity; 1321. Packaging margin; 1322. Weak part; 141. First packaging frame; 142. Second packaging 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

[0072] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0073] In the description of the present 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 the present 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 the present application.

[0074] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0075] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0076] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it 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. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0077] 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 a central 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 a central element at the same time. 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 implementation method.

[0078] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a 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 a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present 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 real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it 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.

[0079] At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries, especially power batteries, are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0080] A battery cell is the smallest unit that makes up a battery. A battery may include one or more battery cells, and multiple battery cells may be connected in series, in parallel, or in a hybrid connection. Among them, a hybrid connection means that multiple battery cells are connected in both series and in parallel.

[0081] After multiple battery cells are connected to each other and arranged in a certain order, they can be directly placed in a box to assemble into a battery. Alternatively, multiple battery cells can be first assembled into a battery module, and then multiple battery modules are connected to each other to form a whole, and finally the whole battery module is placed in a box to form a battery.

[0082] In order to solve the above-mentioned battery thermal runaway problem and reduce the damage and risk to the entire battery.

[0083] See also Figure 1 and Figure 2 An embodiment of the present application provides a composite thermal insulation pad 10 including a composite phase change layer 13 .

[0084] The composite phase change layer 13 includes a phase change material layer 131 and a packaging layer 132 . The packaging layer 132 is disposed on the outer peripheral side of the phase change material layer 131 . A weak portion is disposed on the area of ​​the packaging layer 132 that forms the packaging cavity.

[0085] It can be understood that the encapsulation layer 132 is disposed on the outer peripheral side 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.

[0086] In the composite thermal insulation pad 10, the encapsulation layer 132 is arranged on the outer peripheral side of the phase change material layer 131 to form a composite phase change layer 13, so that the phase change material layer 131 in the composite phase change layer 13 is physically isolated from the outer side of the encapsulation layer 132, and then before the encapsulation layer 132 fails, the phase change material will not diffuse to the outer side of the encapsulation layer 132, causing the loss of the phase change material and causing pollution to the target object that needs insulation, such as the battery cell. In this way, the phase change material in the composite thermal insulation pad 10 can exert better heat absorption performance, and thus play a better thermal insulation performance. At the same time, a weak portion 1322 is provided on 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, so that the encapsulation layer 132 can be broken 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 a battery and has a good effect of preventing thermal runaway of the battery.

[0087] Traditional technology is limited by structure, and phase change materials can only use solid phase change materials, but the heat absorption capacity of solid phase change materials is limited. The above-mentioned composite thermal insulation pad 10, because its phase change material layer 131 is arranged in the packaging cavity of the packaging layer 132, so that the phase change material layer 131 is physically isolated from the first thermal insulation layer 11 and the second thermal insulation layer 12 on both sides, so 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 crystal 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, and its application range is wider, so it can provide better thermal insulation performance.

[0088] 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 a role in 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.

[0089] 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 arranged in the packaging cavity of the packaging layer 132 can prevent moisture overflow from causing adverse effects on the battery.

[0090] In some embodiments, the composite phase change layer 13 also includes a heat-conducting layer disposed in the encapsulation layer 132. Furthermore, the heat-conducting layer is heat-conducting particles or heat-conducting sheets. By disposing the heat-conducting layer in the encapsulation layer 132, on the one hand, the heat-conducting effect of the heat-conducting layer can trigger the phase change material layer 121 also located in the encapsulation layer 132 to undergo a larger area of ​​phase change and absorb heat and cool down. On the other hand, the heat can be diffused to the surroundings, further improving the thermal insulation effect of the composite thermal insulation pad.

[0091] Further, the thermally conductive particles include but are not limited to metal thermally conductive particles, such as copper, aluminum and iron thermally conductive particles. Further, 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. Among them, the metal thermally conductive sheet includes 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 metal sheet or an aluminum metal sheet. In addition, the copper metal sheet has a better effect of suppressing thermal radiation.

[0092] 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 encapsulation layer 132. Further, 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.

[0093] 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 outer thermal insulation layer to form a heat conduction path, and then 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.

[0094] For example, the outer heat insulation layer may be disposed on one side or two opposite sides of the encapsulation layer 132 in the thickness direction of the composite phase change layer 13 .

[0095] In some of the embodiments, the outer thermal insulation layer includes a first thermal insulation layer 11 and a second thermal insulation layer 12, and the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged on both sides of the composite phase change layer 13 in the thickness direction, so that the composite phase change layer 13 is sandwiched between the first thermal insulation layer 11 and the second thermal insulation layer 12. In other words, the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are stacked in sequence.

[0096] 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.

[0097] It is understandable that in other examples, the outer thermal insulation layer may include only the first thermal insulation layer 11 , or only the second thermal insulation layer 12 , and its material and thickness may be the same or similar to those of the first thermal insulation layer 11 or the second thermal insulation layer 12 .

[0098] See also 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.

[0099] 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 0.04-0.06 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. The tensile gauge will display the magnitude of the pulling force when the composite thermal insulation pad is peeled off, and the peeling force is obtained based on the magnitude of the pulling force.

[0100] 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 at 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 play the role of fixing the composite thermal insulation pad 10.

[0101] As an example, the above-mentioned release adhesive layer is provided on the outer surfaces of the first insulation layer 11 and the second insulation layer 12 of the composite insulation pad 10. When in use, the composite insulation pad 10 can be bonded and fixed to two objects respectively through the release adhesive layers on both sides, for example, bonded and fixed to two adjacent battery cells respectively, so that the composite insulation pad 10 is arranged between the two adjacent battery cells.

[0102] like Figure 2 As shown, the first thermal insulation layer 11 and the second thermal insulation layer 12 are physically separated by the composite phase change layer 13. In other words, the edges between the first thermal insulation layer 11 and the second thermal insulation layer 12 are not connected to each other.

[0103] In some embodiments, the length and width of the outer heat 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 heat insulation layer is greater than the corresponding length or width of the composite phase change layer 13.

[0104] See also Figure 4 In some embodiments, the edges of the first thermal insulation layer 11 and the second thermal insulation layer 12 are connected to each other to form an assembly cavity, and the composite phase change layer 13 is located in the assembly cavity. With this structural setting, the composite phase change layer 13 is arranged inside the first thermal insulation layer 11 and the second thermal insulation layer 12, which reduces the risk of the composite phase change layer 13 falling off, and also reduces the risk of leakage when using liquid phase change materials.

[0105] Further, at least one side surface edge 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, at least one side surface edge of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portions of the two are arranged opposite to each other and enclose to form an assembly cavity. Figure 4 In the specific example, convex portions are formed around the edges of one side surface of the first thermal insulation layer 11 and the second thermal insulation layer 12, and the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged opposite to each other and enclose to form an assembly cavity.

[0106] Generally, the two sides of the phase change material layer 131 are encapsulated by an encapsulation film, and there are encapsulation margins on the sides, such as the following Figure 8 That is, the encapsulation layer 132 has an encapsulation margin. When the composite phase change layer 13 is disposed inside the first heat insulation layer 11 and the second heat insulation layer 12, the encapsulation margin is folded and located in the assembly cavity.

[0107] As an example, the encapsulation layer 132 has an encapsulation margin on all four sides.

[0108] See also Figure 5 In some embodiments, the composite thermal insulation pad 10 further includes a third thermal insulation layer 16, and a composite phase change layer 13 is also provided between the second thermal insulation layer 12 and the third thermal insulation layer 16. Furthermore, the composite thermal insulation pad 10 may further include more thermal insulation layers, and the composite phase change layer 13 may also be provided between the second thermal insulation layer 12 and the third thermal insulation layer 16.

[0109] Furthermore, the selection range of the material and thickness 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 material and specific thickness can be the same or different.

[0110] See also Figure 6 and Figure 7 In some embodiments, the composite thermal insulation pad 10 also includes a first packaging frame 141 and a second packaging frame 142. The first packaging frame 141 is arranged on one side of the first thermal insulation layer 11, and the second packaging frame 142 is arranged on one side of the second thermal insulation layer 12. The first packaging frame 141 and the second packaging frame 142 cooperate to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12.

[0111] Further, the first encapsulation frame 141 and the second encapsulation frame 142 are each independently a rubber frame or a silicone frame. In other words, the materials of the first encapsulation frame 141 and the second encapsulation frame 142 are each independently rubber or silicone. Further, the first encapsulation frame 141 and the second encapsulation frame 142 are both rectangular frame structures, such as a square frame, and specifically can be a silicone square frame.

[0112] In such Figure 7and Figure 8 In the example shown, the first packaging frame 141 has a first limiting groove (not shown), the second packaging frame 142 has a second limiting groove (not shown), and the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can limit the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 in the thickness direction and 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. Furthermore, at this time, the packaging margin portion 1321 of the packaging layer 132 can be located between the first packaging frame 141 and the second packaging frame 142, such as Figure 7 As shown, the package margin portion 1321 is pressed in the middle by the first package frame 141 and the second package frame 142 .

[0113] 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 capable of forming 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.

[0114] See also Fig. 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. In this way, the thickness of the composite thermal insulation pad 10 can be minimized, the space it occupies can be reduced, and better thermal insulation performance can be provided.

[0115] As an example, on the basis of the first adhesive layer 151 and the second adhesive layer 152, the first packaging frame 141 and the second packaging frame 142 can be further used to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 around, thereby improving the structural stability of the composite thermal insulation pad 10. Furthermore, at this time, there is no need for the packaging frame to fix the thickness direction, so 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.

[0116] 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 none of them, for example, the first thermal insulation layer 11 is directly formed on the packaging layer 132 of the composite phase change layer 13.

[0117] 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.

[0118] Furthermore, when any of the above-mentioned thermal insulation layers includes both of the thermal insulation felt and the 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 directly formed on the surface of the encapsulation layer 132, and the thermal insulation coating is located between the encapsulation layer 132 and the thermal insulation felt.

[0119] For example, Figure 1 , Figure 3 and Figure 5 In the example, the first thermal insulation layer 11 and the second thermal insulation layer 12 are thermal insulation felts, 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, the overall thickness of the prepared 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.

[0120] For example, in Figure 4 In the example shown, the first thermal insulation layer 11 and the second thermal insulation layer 12 are thermal insulation felts, and the assembly cavity thereon can be integrally formed when the thermal insulation felt is formed, or can be formed by grooving after the thermal insulation felt is formed.

[0121] It is understood that the thermal insulation felt can be connected to the composite phase change layer 13 through the above-mentioned adhesive layer or packaging frame. The thermal insulation coating can be directly formed on the packaging layer 132 in the composite phase change layer 13. As an example, the thermal insulation coating can be prepared by coating the packaging layer 132 of the composite phase change layer 13 with a slurry and then drying it to form a coating.

[0122] In some embodiments, the outer insulation layer is a ceramic material layer.

[0123] Furthermore, the thermal insulation felt may be a ceramic thermal insulation felt; further, the thermal insulation coating may be a ceramic thermal insulation coating. It is understood that the ceramic thermal insulation felt and the ceramic thermal insulation coating are both 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 13 are each independently a ceramic material layer.

[0124] The material in the "ceramic material layer" in the present 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.

[0125] 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.

[0126] 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.

[0127] In some of the 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.

[0128] In some embodiments, the density of the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 16 are independently 0.2-0.22 g / cm 3 .

[0129] 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, it can be 0.15:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1.

[0130] 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, 8 mm; it can be optionally 1 mm to 8 mm.

[0131] In this article, the following method can be used to test the thickness of the composite thermal insulation pad. The equipment used is: Mitutoyo 547-301 thickness gauge, equipment accuracy: ≤0.01mm; during the test, the test surface of the composite thermal insulation pad and Mitutoyo 547-301 thickness gauge are required to be parallel to the ground, and the test positions are 5 points in the four corners and the center area, and the average value of the 5 points is taken as the test value. For example, the thickness of the outer insulation layer.

[0132] In some of the embodiments, the thickness of the first thermal insulation layer 11 is 0.5 mm to 8 mm. For example, the thickness may be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm.

[0133] In some of the embodiments, the thickness of the second thermal insulation layer 12 is 0.5 mm to 8 mm. For example, the thickness may be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm.

[0134] Furthermore, the thickness of the second heat insulation layer 12 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.

[0135] In some of the embodiments, the thickness of the composite phase change layer 13 is 1 mm to 6 mm, and can be 1 mm to 4 mm. As an example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm. It can also be 1.5 mm to 3.5 mm.

[0136] In some of the embodiments, the thickness of the packaging layer 132 is 0.1 mm to 0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and can be optionally 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0137] 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).

[0138] It can be understood that the weak portion 1322 on the packaging layer 132 is a relatively weak area on the packaging layer 132 .

[0139] In some embodiments, the weak portion 1322 is a region with a relatively thin thickness and / or relatively weak material strength. In other words, the weak portion 1322 may be a region with a relatively thin thickness but a constant material strength, which may be formed by locally thinning the encapsulation layer 132. The weak portion 1322 may also be a region with a constant thickness but a relatively weak material strength, which may be formed by locally weakening the material strength of the encapsulation layer 132, for example, by using materials of different strengths. It may also be a region with a relatively thin thickness and a relatively weak material strength. It is understood that the material strength here refers to the strength of the material itself.

[0140] Further, the weak portion 1322 is a notch area formed on the packaging layer 12. It can be understood that the notch area is formed by thinning the surface of the packaging layer in the form of engraving and pressing, and the thickness of the notch area is relatively thin.

[0141] Furthermore, the weak portion 1322 may 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.

[0142] Furthermore, the depth of the weak portion 1322 accounts for 15% to 50% of the thickness of the packaging layer 132, for example, 15%, 20%, 30%, 35%, 40%, 45%, 50%. By controlling the thickness ratio, the packaging layer 132 can take into account both a better isolation effect when no package breakage is required and a better timely package breakage effect in the event of thermal runaway.

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

[0144] Furthermore, when the encapsulation layer 132 is an aluminum-plastic film, the weak portion penetrates 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 into the aluminum foil layer, but does not penetrate the aluminum foil layer, and is further controlled to penetrate to 30% to 60% of the thickness of the aluminum foil layer, so that the encapsulation layer 132 can take into account both better isolation when no package breaking is required and better timely package breaking in case 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 encapsulation layer 132 includes a polypropylene layer, an aluminum foil layer, a nylon layer, and a polyester layer stacked from the inside to the outside. As a specific example, 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, and the weak portion 1322 can penetrate from one side of the polyester layer to a position where the aluminum foil layer is half the thickness.

[0147] In some embodiments, the phase change material layer 131 includes a heat insulating substrate 1311 (eg Figure 2 As shown) and phase change material, 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.

[0148] Furthermore, the thermal insulation substrate 1311 may be a ceramic material substrate, such as ceramic fiber felt.

[0149] Furthermore, in some examples, at least part of the phase change material is directly filled in the pores of the thermal insulation substrate 1311. In other examples, at least part 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 can be understood that in the same thermal insulation substrate 1311, two states of phase change materials can also be included at the same time, one is that the phase change material is directly filled in the pores of the thermal insulation substrate 1311, and the other is that the phase change material is filled in the pores of the thermal insulation substrate 1311 in the form of phase change microcapsules.

[0150] It can be understood that the phase change material layer 131 can be obtained by soaking the porous thermal insulation substrate 1311 such as ceramic fiber felt in a liquid phase change material, for example, soaking in a molten phase change material and then cooling it or soaking in a phase change material solution and then drying or heat preservation. In addition to absorbing heat, the phase change material layer 131 can also play a role in heat insulation. When the phase change material vaporizes and breaks the packaging 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 play a role in heat insulation. In other words, the phase change material is directly filled in the pores of the thermal insulation substrate 1311.

[0151] 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, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material. It can be understood that in some examples, the pores of the thermal insulation substrate 1311 can also be directly filled with the phase change material and the above-mentioned phase change microcapsules at the same time.

[0152] 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 to fill the phase change microcapsules in the pores of the thermal insulation substrate 1311, and removing the solvent in the phase change microcapsule dispersion.

[0153] 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 insulation pad 10 vaporizes and breaks the packaging layer 132, that is, the composite insulation pad 10 fails. At this time, the insulation substrate 1311 in the phase change material layer 131 can continue to play an insulation role.

[0154] Further, the wall material includes a polymer matrix and ceramic particles filled in the polymer matrix. Further, the mass ratio of the polymer matrix to the ceramic particles is 3:(7-11), and as an example, the mass ratio of the polymer matrix to the ceramic particles can be 3:7, 3:8, 3:9, 3:10, 3:11. By controlling the mass content of the ceramic particles in the wall material to be larger, the pressure resistance and heat insulation capacity of the wall material can be improved.

[0155] 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, 1:1.6. This can further improve the pressure resistance of the phase change microcapsule.

[0156] 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, but also has good compatibility with phase change materials such as paraffin wax, can form a stable interface with the phase change material, and improve the thermal stability of the phase change microcapsules.

[0157] Furthermore, the Dv50 particle size of the phase change microcapsule is 5 to 8 μm. The Dv50 particle size is the volume average particle size Dv50, which indicates the particle size corresponding to when the cumulative volume distribution percentage of the particles reaches 50%, and can be tested by methods known in the art. For example, it can be measured using a laser particle size analyzer (such as Malvern Master Size 3000).

[0158] 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.

[0159] Furthermore, the melting point of the wall material is greater than 98° C. The wall material has a relatively high melting point, and can maintain the structural stability of the microcapsule within the phase change temperature range of the phase change material.

[0160] 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.

[0161] 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.

[0162] Phase-change microcapsules can be obtained by in-situ polymerization, where the wall material covers 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, stirring to form a Pickering emulsion, adding the raw materials required for preparing 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 generate a non-water-soluble polycondensate (i.e., a polymer matrix) with a cross-linked three-dimensional network structure at the interface of the emulsion.

[0163] The polymer matrix of the above material has better compatibility with phase change materials such as paraffin, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of phase change microcapsules.

[0164] 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.

[0165] It can be understood that the phase change material layer 131 includes the above-mentioned heat insulation substrate 1311 and the phase change material filled in the pores of the heat insulation substrate 1311, and the phase change material layer 131 is located in the packaging cavity. In other words, the heat insulation substrate 1311 is also located in the packaging cavity. Figure 2 Furthermore, there is a distance between at least one side edge 1311a of the thermal insulation substrate 1311 located in the packaging cavity and the inner wall 132a of the packaging cavity, and the weak portion 1322 is provided on the packaging layer 132 and is located between the edge 1311a of the thermal insulation substrate 1311 and the inner wall 132a of the packaging cavity.

[0166] It can be understood that since the encapsulation layer 132 is arranged on the outer surface of the phase change material layer 131 and forms an encapsulation cavity, the encapsulation layer 132 includes a first area bonded to the first thermal insulation layer 11, a second area bonded to the second thermal insulation layer 12, and a third area connecting the first area and the second area, and the weak portion 1322 is arranged on the first area and / or the second area 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 on the area where the encapsulation layer 132 forms the above-mentioned gap. The inner wall 32a of the encapsulation cavity here refers to the inner wall of the encapsulation cavity facing the side edge 1311a of the thermal insulation substrate 1311, that is, the third area facing the side edge 1311a of the thermal insulation substrate 1311.

[0167] Furthermore, the two relative surfaces of the thermal insulation substrate 1311 are bonded to the relative inner walls of the encapsulation layer, that is, the two relative surfaces of the thermal insulation substrate 1311 are respectively bonded to the first area and the second area of ​​the encapsulation layer 132. The side edge of the thermal insulation substrate 1311 is the edge connecting the two relative 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 edges on all sides of the thermal insulation substrate 1311. Reserving this gap can, on the one hand, prevent the stress between the edges on all sides 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.

[0168] Furthermore, the distance h1 between the weak portion 1322 and the edge 1311a of the heat insulating substrate 1311 is controlled to be 2-7 mm, optionally 2-5 mm, and more optionally 4-5 mm. When other conditions remain unchanged, the size of the bag breaking force is related to the distance between the weak portion and the edge of the heat insulating substrate 1311.

[0169] like Figure 10~Figure 12 As shown, the stress-strain curve of the composite thermal insulation pad at different positions of the weak part is 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 be tested at an inlet stress of 0.008MPa, and the equipment compresses to a certain pressure at a compression rate of 2mm / min, and records the compression stress-strain curve. The test was carried out in an environment with a temperature of 23℃±5℃, a relative humidity of 45%~75%, and an atmospheric pressure of 86kPa~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.

[0170] The stress test equipment is a pressure tester produced by Xiamen Yinghaoda, with a measuring pressure range of 1-8KN and a measuring area of ​​300*300mm. Stress = load force / sample area.

[0171] 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 the displacement relative to the initial position recorded by a micrometer or pressure tester; the equipment used for the initial thickness of the sample is as follows: Mitutoyo 547-301 thickness gauge, equipment accuracy: ≤0.01mm; during the test, the test surfaces of the composite insulation pad and Mitutoyo 547-301 thickness gauge are required to be parallel to the ground, and the test positions are 5 points in 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 a micrometer or pressure tester / initial thickness of the sample

[0172] 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.

[0173] Furthermore, in a specific example, Fig.10 As shown, when other conditions remain unchanged, when the distance h1 between the weak portion 1322 and the edge 1311a of the heat insulation substrate 1311 is 2-3 mm, the bag breaking force is 0.28 MPa; Fig.11 As shown, when the distance h1 between the weak portion 1322 and the edge 1311a of the heat insulating substrate 1311 is 4-5 mm, the breaking force is 0.38 MPa; Fig.12 As shown, when the distance h1 between the weak portion 1322 and the edge 1311a of the heat insulation substrate 1311 is 6-7 mm, the bag breaking force is 1.69 MPa.

[0174] Optionally, in order to enable the encapsulation layer 132 to break more quickly and timely in thermal runaway and discharge gas, the distance h1 between the weak portion 1322 and the edge 1311a of the thermal insulation substrate 1311 is controlled to be 4-5 mm.

[0175] Furthermore, a distance h2 between the weak portion 1322 and the inner wall 132a of the packaging cavity is greater than 3 mm, and may be 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 .

[0176] Further, the weak portion 1322 is linear. Further, the extension direction of the weak portion 1322 is the same as the extension direction of the edge 1311a of the heat insulation substrate 1311. It can be understood that in other examples, the weak portion 1322 can also be arc-shaped, etc., and is not limited thereto.

[0177] Furthermore, the total length of the weak portion 1322 accounts for 50% to 100% of the length of the edge of the heat insulation substrate 1311; it 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 break the package in time due to thermal runaway.

[0178] Furthermore, there are multiple weak portions 1322, which are spaced apart along the extending direction of the edge 1311a of the heat insulating substrate 1311. The length of each weak portion 1322 is 1 / 20 to 1 / 10 of the edge 1311a of the heat insulating substrate 1311, for example, 1 / 20, 1 / 15, or 1 / 10.

[0179] In a specific example, the weak portion 1322 is a notched area, and the length of the weak portion 1322 is 5-20 mm, and the width of the weak portion 1322 is 0.5-2 mm.

[0180] See also 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 , and the composite thermal insulation pad 10 is disposed between at least two adjacent battery cells 20 .

[0181] 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 has 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 to achieve the effect of slowing down the thermal runaway of the battery. 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 a gaseous state and breaks through 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.

[0182] 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.

[0183] It is understood that the shape of the battery cell 20 includes but is not limited to a square or a cylinder. The composite thermal insulation pad 10 can be arranged in a manner that is consistent with the shape of the battery cell 20 .

[0184] In some of the 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.

[0185] Furthermore, the composite thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0186] In this application, unless otherwise specified, "battery cell 20" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0187] It is understandable that after a plurality of battery cells 20 are connected to each other and arranged in a certain order, they can be directly placed in a box to assemble into a battery. Alternatively, a plurality of battery cells 20 can be first formed into a battery module, and then a plurality of battery modules are connected to each other to form a whole, and finally the whole battery module is placed in a box to form a battery.

[0188] For example, Fig.15 It is a battery cell 20 of a square structure as an example. The battery cell 20 includes a shell 21, a cover plate 23 and an electrode assembly 22. The electrode assembly 22 is accommodated in the shell 21. The shell 21 is provided with an opening, and the cover plate 23 is sealed in the opening. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the negative electrode sheet and the separator can be formed by a winding process or a lamination process. Furthermore, the electrode assembly 22 also includes an electrolyte, such as an electrolyte. The electrolyte is infiltrated 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.

[0189] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0190] Further, the housing 21 is a rectangular housing, and the opening direction of the housing 21 is the height direction of the housing 21. Further, both ends of the housing 21 are provided with openings, and the two openings are arranged oppositely along the height direction 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.

[0191] Furthermore, the battery cell 20 and the shell 21 are rectangular shells, and the composite insulation pad 10 is arranged on the larger side of the battery cell 20, which 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.

[0192] As a further non-limiting example, the wall thickness of the housing 21 is 0.5 mm to 0.8 mm.

[0193] Furthermore, the housing 21 is an aluminum alloy housing; for example, a three-series aluminum alloy housing or a five-series aluminum alloy housing.

[0194] Furthermore, the aluminum alloy of the three-series aluminum alloy shell includes the following components in mass percentage: 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%.

[0195] Furthermore, the aluminum alloy of the fifth series aluminum alloy shell includes the following components in mass percentage: 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 composition of other elements ≤ 0.15%.

[0196] Another embodiment of the present application further provides an electrical device, including the above-mentioned battery provided in the present application. The above-mentioned battery can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto. Among them, the mobile device may be, for example, a mobile phone, a laptop computer, etc.; the electric vehicle may be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc., but are not limited thereto.

[0197] Fig.16 The power consumption device 40 is taken as an example. The power consumption device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of secondary batteries, a battery pack or a battery module may be used.

[0198] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0199] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0200] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A composite thermal insulation pad, characterized in that: include: A 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 area of ​​the encapsulation layer constituting the encapsulation cavity; the phase change material layer comprises a heat insulation substrate and a phase change material, wherein the heat insulation substrate is arranged in the encapsulation cavity of the encapsulation layer, and the phase change material is filled in the heat insulation substrate.

2. The composite thermal insulation pad according to claim 1, characterized in that: The weak portion is a region with a relatively thin thickness and / or relatively weak material strength.

3. The composite thermal insulation pad according to claim 1, characterized in that: The weak portion is a notch area formed in the packaging layer.

4. The composite thermal insulation pad according to claim 1, characterized in that: 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. The core material includes the phase change material.

5. The composite thermal insulation pad according to claim 4, characterized in that: The Dv50 particle size of the phase change microcapsule is 5 μm to 8 μm.

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

7. The composite thermal insulation pad according to claim 6, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The 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, characterized in that: 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 parts, and the multiple weak parts are arranged at intervals along the extension direction of the edge of the thermal insulation substrate. The length of each weak part 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, characterized in that: 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, characterized in that: 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 disposed 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 9, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: The encapsulation 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 penetrates 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 9, characterized in that: The composite thermal insulation pad further comprises an outer thermal insulation layer, and the outer thermal insulation layer is arranged on at least one side of the outer peripheral side of the packaging layer.

13. The composite thermal insulation pad according to claim 12, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The outer 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 heat insulation layer is 0.15 to 12:1; (4) The outer heat insulation layer is disposed 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 heat 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 heat insulation layer is greater than the corresponding length or width of the composite phase change layer.

14. The composite thermal insulation pad according to claim 12, characterized in that: The outer heat insulation layer includes a first heat insulation layer and a second heat insulation layer; The first heat insulation layer and the second heat 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 heat insulation layer and the second heat insulation layer.

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

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

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

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

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

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

21. The composite thermal insulation pad according to claim 18, characterized in that: The outer surface of the first heat insulation layer is flush with the outer surface of the first packaging frame, and / or the outer surface of the second heat insulation layer is flush with the outer surface of the second packaging frame.

22. The composite thermal insulation pad according to any one of claims 14 to 21, characterized in that: The composite thermal insulation pad also includes a third thermal insulation layer, and the composite phase change layer is also arranged 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 9, characterized in that: 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, characterized in that: Comprising a composite thermal insulation pad as described in any one of claims 1 to 23.

25. The battery according to claim 24, 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.

26. The battery according to claim 25, characterized in that The composite heat-insulating pad is arranged between the large surfaces of two adjacent battery cells.

27. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 24 to 26.

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