Thermal insulation pad, battery and electric device

Abstract

The present application relates to a thermal insulation pad, a battery and an electric device. The thermal insulation pad comprises a thermal insulation pad body and a strain detection member, wherein the strain detection member is arranged in the thermal insulation pad body. The thermal insulation pad is applied to a battery, and has the effect of slowing down thermal runaway of the battery, and by means of the strain detection member arranged in the thermal insulation pad, the state of the battery during use can be accurately obtained.

Description

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 202420290182X, entitled “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 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 are demanding higher performance, such as higher energy density. However, battery cells with higher energy density have high residual energy after thermal runaway. When one cell experiences thermal runaway, the heat from one cell continuously transfers to adjacent cells, causing heat diffusion throughout the battery and damaging the entire battery. Therefore, how to determine the battery's current status and mitigate thermal runaway are urgent issues that need to be addressed.

[0005] Summary of the Invention

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

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

[0008] the thermal insulation pad body; and

[0009] The strain detection component is arranged on the thermal insulation pad body.

[0010] The thermal insulation pad described above in this application can be applied to batteries and has the function of slowing down thermal runaway of the battery. In addition, a strain detector is provided on the thermal insulation pad body. The pressure parameters of the thermal insulation pad can be obtained based on the electrical signal output by the strain detector. In this way, when the thermal insulation pad is applied to a battery, the expansion state of the battery during use can be obtained through the strain detector. It can also be known whether the packaging layer is crushed and failed during the use of the battery. In this way, the strain detector provided in the thermal insulation pad can accurately obtain the state of the battery during use.

[0011] In some embodiments, the thermal insulation pad body includes an outer insulation layer, and the strain detection component is located within the outer insulation layer or is provided on the outer surface of the outer insulation layer. In some embodiments, the strain detection component is provided on the outer surface of the outer insulation layer, and the thermal insulation pad further includes a waterproof protective film provided on the outer surface of the strain detection component.

[0012] In some embodiments, the strain detection component has an external wire, and the external wire is led out from one side of the outer thermal insulation layer.

[0013] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0014] (1) The ratio of the thickness of the strain detection member to the thickness of the outer heat insulation layer is 1:(10-500);

[0015] (2) The thickness of the strain detection member is 10 μm to 50 μm;

[0016] (3) The thickness of the outer insulation layer is 0.5 mm to 8 mm;

[0017] (4) The outer thermal insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K;

[0018] (5) The density of the outer insulation layer is 0.2 g / cm 3 ~0.22g / cm 3 ;

[0019] (6) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating;

[0020] (7) The outer heat insulation layer is a ceramic material layer;

[0021] (8) The strain of the outer insulation layer when subjected to a stress of 0.5 MPa to 5 MPa is 25% to 70%;

[0022] (9) The thermal insulation pad also includes a release adhesive layer, which includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

[0023] In some embodiments, the thermal insulation pad body also includes a composite phase change layer, which includes a phase change material layer and an encapsulation layer, and the encapsulation layer is arranged on the outer peripheral side of the phase change material layer; the outer thermal insulation layer is arranged on at least one side of the composite phase change layer.

[0024] The outer thermal insulation layer is arranged on at least one side of the composite phase change layer. The phase change material layer in the encapsulation layer can absorb the heat transferred from the outer thermal insulation layer to play a thermal insulation role. On the other hand, 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 thermal insulation layer. Therefore, before the encapsulation layer 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 thermal insulation pad.

[0025] In some embodiments, the strain detection member has a first surface away from the composite phase change layer, the outer heat insulation layer has a second surface away from the composite phase change layer, and the distance between the first surface and the second surface is ≥0.3 mm.

[0026] In some embodiments, the distance between the first surface and the second surface is 0.3 mm to 0.5 mm.

[0027] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0028] (1) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm;

[0029] (2) The thickness of the composite phase change layer is 1 mm to 6 mm;

[0030] (3) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer;

[0031] (4) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is (0.15-12):1;

[0032] (5) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film;

[0033] (6) The thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the encapsulation layer are connected via the adhesive layer;

[0034] (7) 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;

[0035] (8) 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. In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0036] (9) The strain of the composite phase change layer is 8% to 20% when subjected to a stress of 0.5 MPa to 5 MPa.

[0037] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

[0042] In some embodiments, the 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0047] (1) The strain of the thermal insulation pad when subjected to a stress of 0.5 MPa to 4 MPa is 15% to 35%;

[0048] (2) The 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 phase change material layer includes a thermal insulation substrate and a phase change material;

[0050] Wherein, the phase change material is filled in the thermal insulation substrate.

[0051] In some embodiments, the phase change material is filled in the pores of 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.

[0052] In a second aspect, the present application provides a battery comprising the above-mentioned thermal insulation pad.

[0053] In some embodiments, a plurality of battery cells are further included, and the thermal insulation pad is disposed between at least two adjacent battery cells.

[0054] In some embodiments, the thermal insulation pad is disposed between the large surfaces of two adjacent battery cells.

[0055] In a third aspect, the present application provides an electrical device comprising the battery as described above.

[0056] 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

[0057] 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.

[0058] FIG1 is a schematic cross-sectional view of a thermal insulation pad according to an embodiment of the present application;

[0059] FIG2 is a schematic cross-sectional view of a thermal insulation pad according to another embodiment of the present application;

[0060] FIG3 is a schematic cross-sectional view of a thermal insulation pad according to another embodiment of the present application;

[0061] FIG4 is a schematic cross-sectional view of a thermal insulation pad according to another embodiment of the present application;

[0062] FIG5 is a schematic diagram of the three-dimensional structure of a thermal insulation pad according to another embodiment of the present application;

[0063] FIG6 is a schematic cross-sectional view of the thermal insulation pad shown in FIG5 taken along the AA direction;

[0064] FIG7 is an exploded cross-sectional view of the thermal insulation pad shown in FIG6 ;

[0065] FIG8 is a schematic cross-sectional view of a thermal insulation pad according to another embodiment of the present application;

[0066] FIG9 is a schematic structural diagram of a battery according to an embodiment of the present application;

[0067] FIG10 is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0068] FIG11 is a schematic structural diagram of a battery cell in a battery according to one embodiment;

[0069] FIG12 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application;

[0070] FIG13 is a graph showing the thermal insulation performance of the thermal insulation mat obtained in Example 1;

[0071] FIG14 is a graph showing the thermal insulation performance of the thermal insulation pad prepared in Example 2;

[0072] FIG15 is a compressive stress-strain curve of a single composite phase change layer in Example 1;

[0073] FIG16 is a compressive stress-strain curve diagram of the first thermal insulation layer alone in Example 1;

[0074] FIG17 is a compressive stress-strain curve diagram of the thermal insulation pad as a whole in Example 1. FIG.

[0075] Explanation of the accompanying drawings: 10. Thermal insulation pad; 11. First thermal insulation layer; 12. Second thermal insulation layer; 13. Composite phase change layer; 131. Phase change material layer; 132. Packaging layer; 1321. Packaging margin; 141. First packaging frame; 142. Second packaging frame; 151. First adhesive layer; 152. Second adhesive layer; 16. Third thermal insulation layer; 17. Strain detection part; 172. External wire; 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, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[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] 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.

[0083] 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.

[0084] 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.

[0085] In order to solve the above-mentioned battery thermal runaway and reduce the damage and risk to the entire battery.

[0086] Referring to FIG1 , one embodiment of the present application provides a thermal insulation pad 10, comprising a thermal insulation pad body and a strain detection member 17. The strain detection member 17 is disposed on the thermal insulation pad body. Furthermore, the strain detection member 17 is disposed within the thermal insulation pad body or on the outer surface of the thermal insulation pad body.

[0087] The strain detection member 17 is a component used to detect stress parameters. Generally, it includes a flexible layer and a strain detection element layer provided on the flexible layer. The flexible layer can deform synchronously with the thermal insulation layer in which it is located. The strain detection element layer can convert the deformation of the flexible layer into an electrical signal output, such as a voltage signal.

[0088] The above-mentioned thermal insulation pad 10 can be applied to batteries and has the function of slowing down thermal runaway of the battery. In addition, a strain detection part 17 is provided on the thermal insulation pad body. According to the electrical signal output by the strain detection part 17, the pressure parameters of the thermal insulation pad 10 can be obtained, that is, the stress of the thermal insulation pad 10 can be monitored. For example, the volume of the battery cells of the battery expands during use, which causes the pressure between adjacent battery cells to change. In this way, when the thermal insulation pad 10 is applied to the battery, the expansion state of the battery during use can be obtained through the strain detection part 17. In addition, the packaging layer 132 of the thermal insulation pad 10 will also cause the pressure between adjacent battery cells to change before and after failure. Therefore, the strain detection part 17 can also be used to know whether the packaging layer 132 is crushed and failed during the use of the battery. In this way, the state of the battery during use can be accurately obtained through the strain detection part 17 provided in the thermal insulation pad 10.

[0089] In some embodiments, the thermal insulation pad body includes an outer thermal insulation layer. The strain detection member 17 is disposed on the outer thermal insulation layer. Furthermore, the strain detection member 17 can be disposed within the outer thermal insulation layer or on the outer surface of the outer thermal insulation layer.

[0090] It is understood that the strain detection element 17 may be disposed within the outer thermal insulation layer, including but not limited to a portion or the entirety of the strain detection element 17 being located within the outer thermal insulation layer. The entirety of the strain detection element 17 being located within the outer thermal insulation layer includes but is not limited to a portion of the surface of the strain detection element 17 being flush with the outer thermal insulation layer, i.e., such portion of the surface is uncovered by the thermal insulation layer and is exposed, and also includes the entirety of the surface of the strain detection element 17 being covered by the outer thermal insulation layer, i.e., the entirety of the strain detection element 17 being located within the outer thermal insulation layer.

[0091] In some embodiments, the thermal insulation pad body further includes a composite phase change layer 13, which includes a phase change material layer 131 and an encapsulation layer 132, wherein the encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131. An outer thermal insulation layer is disposed on at least one side of the outer periphery of the encapsulation layer 132.

[0092] In the aforementioned thermal insulation pad 10, on the one hand, the outer insulation layer is disposed on at least one side of the outer periphery of the encapsulation layer 132. The phase change material layer 131 within the encapsulation layer 132 can absorb heat transferred from the outer insulation layer to provide insulation. On the other hand, the encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 to form a composite phase change layer 13, so that the phase change material layer 131 in the composite phase change layer 13 is physically isolated from the outer insulation layer. Therefore, before the encapsulation layer 132 fails, the phase change material will not diffuse into the outer insulation layer to form a heat conduction path, and thus will not change the structure of the outer insulation layer and its insulation performance, thereby improving the insulation performance of the thermal insulation pad. When applied to batteries, the aforementioned thermal insulation pad has an excellent effect in preventing thermal runaway of the battery.

[0093] 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 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, silicone oil, silica sol, aluminum sol, silica aluminum sol, paraffin, 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.

[0094] 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.

[0095] 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.

[0096] Furthermore, the outer heat insulation layer may be provided on at least one of the two sides in the thickness direction of the composite phase change layer 13 .

[0097] 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 .

[0098] In some embodiments, the outer insulation layer includes a first insulation layer 11 and a second insulation layer 12. The first insulation layer 11 and the second insulation layer 12 are disposed on opposite sides of the composite phase change layer 13 in the thickness direction, such that the composite phase change layer 13 is sandwiched between the first insulation layer 11 and the second insulation layer 12. In other words, the first insulation layer 11, the composite phase change layer 13, and the second insulation layer 12 are stacked in sequence. The encapsulation layer 132 is disposed on the outer periphery of the phase change material layer 131 and forms an encapsulation cavity. The phase change material layer 131 is disposed within the encapsulation cavity.

[0099] The above-mentioned 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. 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 thermal insulation pad 10.

[0100] 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 .

[0101] In some specific examples, the thermal insulation pad 10 is strained by applying pressure. For example, in the process of strain from 0 to point A, the greater the strain, the greater the stress detected by the strain detection element 17. This is the deformation state of the packaging layer 132 in the thermal insulation pad 10 before failure. When reaching point A, the pressure is continued to be applied, the strain continues to increase, but the stress detected by the strain detection element 17 decreases. This is because the external pressure is too large, causing the packaging layer 132 to collapse and fail, which in turn causes a sudden change in stress and rapid stress relief. After that, as the strain increases, the stress will continue to increase. In this way, the state of the thermal insulation pad 10 can be known by the stage of the stress curve detected by the strain detection element 17. When applied to batteries, the state of the battery cells adjacent to the thermal insulation pad 10 can also be known.

[0102] In the specific example shown in FIG1 , the strain detection element 17 is disposed in the second thermal insulation layer 12, and the strain detection element 17 is entirely located within the second thermal insulation layer 12. It is understood that the strain detection element 17 may also be disposed in the first thermal insulation layer 11, or in both the first thermal insulation layer 11 and the second thermal insulation layer 12.

[0103] Furthermore, the strain sensing element 17 has a first surface that is distal to the composite phase change layer 13, and the outer thermal insulation layer on which the strain sensing element 17 is provided has a second surface that is distal to the composite phase change layer 13. The distance between the first and second surfaces is ≥ 0.3 mm, and can be selected from 0.3 mm to 0.5 mm, and more preferably from 0.3 mm to 0.45 mm. Both the first and second surfaces are outer surfaces that are distal to the composite phase change layer 13. This allows the thermal insulation pad to protect the strain sensing element 17 while maintaining its sensitivity.

[0104] It can be understood that the strain detection element 17 is provided on the surface of the outer heat insulation layer, which may be the surface opposite to the composite phase change layer 13 or the surface opposite to the composite phase change layer 13 .

[0105] Optionally, the strain detector 17 is located on the outer surface of the outer insulation layer, which allows for a more rapid response to stress changes. Furthermore, the insulation pad 10 may also include a waterproof protective film (not shown) located on the outer surface of the strain detector 17 to protect it from moisture and extend its service life.

[0106] Furthermore, the strain detector 17 also has an external wire 172, which is led out from one side of the corresponding insulation layer for connection to the low-voltage connection line in the battery. Optionally, the external wire 172 is led out from the shorter side of the corresponding insulation layer for easier wiring.

[0107] It can be understood that, generally, the strain detection element 17 also has two external wires 172 , through which the strain electrical signal converted from the deformation can be output to the outside.

[0108] In some embodiments, the ratio of the thickness of the strain detection member 17 to the thickness of the outer heat insulation layer is 1:(10-500).

[0109] Furthermore, the thickness of the strain detection element 17 is 10 μm to 50 μm. As an example, the thickness of the strain detection element 17 may be 13 μm. It is understood that the thickness here refers to the sum of the thicknesses of the flexible layer and the strain detection element layer.

[0110] In some embodiments, the first insulation layer 11 is a ceramic material layer. Further, the thickness of the first 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, 8 mm; optionally, it can be 1 mm to 8 mm.

[0111] In some embodiments, the second thermal insulation layer 12 is a ceramic material layer. Further, the thickness of the second thermal insulation layer 12 is 0.5 mm to 8 mm, and as an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; optionally, it can be 1 mm to 8 mm.

[0112] Referring to FIG. 2 , in some embodiments, the thermal insulation pad 10 further includes an adhesive layer, and the outer thermal insulation layer is connected to the encapsulation layer 132 via the adhesive layer. Furthermore, the adhesive layer includes a first adhesive layer 151 and a second adhesive layer 152. The first thermal insulation layer 11 is connected to the encapsulation layer 132 via the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 via the second adhesive layer 152. In this way, the first thermal insulation layer 11, the composite phase change layer 13, and the second thermal insulation layer 12 of the thermal insulation pad 10 are connected and fixed in the thickness direction via the adhesive layer.

[0113] Furthermore, the first adhesive layer 151 and the second adhesive layer 152 are each independently made of silicone adhesive, and each has a thickness of 0.04 to 0.06 mm. The silicone adhesive layer is heat-resistant and has high structural strength. The resulting thermal insulation pad has a peel force greater than 10 N / cm. The peel force can be measured by pulling the two sides of the thermal insulation pad with a tensile gauge and applying a force perpendicular to the pad at 90 degrees to the two sides. The tensile gauge will display the pulling force when the thermal insulation pad is peeled off, and the peel force can be calculated based on the pulling force.

[0114] In some embodiments, the 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 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 thermal insulation pad 10 is removed, and the thermal insulation pad 10 is simply and conveniently fixed to the target position by bonding with the third adhesive layer, thereby fixing the thermal insulation pad 10.

[0115] As an example, the aforementioned release adhesive layers are provided on the outer surfaces of the first insulation layer 11 and the second insulation layer 12 of the thermal insulation pad 10. During use, the thermal insulation pad 10 can be bonded and fixed to two objects using the release adhesive layers on both sides, for example, to two adjacent battery cells, so that the thermal insulation pad 10 is positioned between the two adjacent battery cells.

[0116] 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.

[0117] 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.

[0118] Referring to Figure 3 , in some embodiments, the edges of the first and second thermal insulation layers 11, 12 are connected to form an assembly cavity, within which the composite phase change layer 13 is located. This structural arrangement allows the composite phase change layer 13 to be positioned within the first and second thermal insulation layers 11, 12, reducing the risk of the composite phase change layer 13 falling off.

[0119] 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 3, 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.

[0120] 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 FIG. 7 . 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.

[0121] As an example, the encapsulation layer 132 has an encapsulation margin on all four sides.

[0122] Referring to Figure 4, in some embodiments, the 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 thermal insulation pad 10 may further include more thermal insulation layers, each of which may also have the aforementioned composite phase change layer 13 provided between adjacent thermal insulation layers.

[0123] 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.

[0124] Please refer to Figures 5 and 6. In some embodiments, the 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.

[0125] Furthermore, the first packaging frame 141 and the second packaging frame 142 are each independently a rubber frame or a silicone frame. In other words, the first packaging frame 141 and the second packaging frame 142 are each independently made of rubber or silicone. Furthermore, the first packaging frame 141 and the second packaging frame 142 are both shaped like a truncated frame, such as a silicone truncated frame.

[0126] In the example shown in Figures 6 and 7, the first encapsulation frame 141 has a first limiting groove (not shown), the second encapsulation frame 142 has a second limiting groove (not shown), and the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can limit the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 in the thickness direction and the radial direction of the thermal insulation pad 10, thereby improving the structural stability of the thermal insulation pad 10. Among them, the radial direction of the thermal insulation pad 10 refers to the direction from the center of the thermal insulation pad 10 to the edge of the thermal insulation pad 10. Further, at this time, the encapsulation margin 1321 of the encapsulation layer 132 can be located between the first encapsulation frame 141 and the second encapsulation frame 142. As shown in Figure 7, the encapsulation margin 1321 is pressed in the middle by the first encapsulation frame 141 and the second encapsulation frame 142.

[0127] 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.

[0128] Referring to Figure 8 , 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 thermal insulation pad 10 and reduce the space it occupies while providing better thermal insulation performance.

[0129] 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 thermal insulation pad 10. Furthermore, in this case, the packaging frame is no longer required to secure the material in the thickness direction, thereby achieving a level outer surface between the first thermal insulation layer 11 and the first packaging frame 141, and a level outer surface between the second thermal insulation layer 12 and the second packaging frame 142.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] For example, in the examples of Figures 1, 3 and 6, 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 can also be thermal insulation coatings. In comparison, the thickness of the thermal insulation coating is thinner, the overall thickness of the thermal insulation pad is thinner, and the required space is relatively smaller. The thermal insulation layer of the 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.

[0134] Taking Figure 1 as an example, when a strain detector 17 is provided in the second thermal insulation layer 12, a groove for accommodating the strain detector 17 can be first formed in the second thermal insulation layer 12. After the strain detector 17 is placed in the groove, thermal insulation felt can be filled to cover the strain detector 17. Specifically, the strain detector 17 can be fixed to the thermal insulation felt by an adhesive layer.

[0135] For example, in the example shown in FIG5 , 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.

[0136] 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.

[0137] 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 13 described above are each independently a ceramic material layer.

[0138] The material of the "ceramic material layer" in this application includes, but is not limited to, at least one of ceramic oxides, ceramic nitrides, and ceramic carbides. Among them, ceramic oxides include, but are not limited to, silicon oxide and aluminum oxide; ceramic nitrides include, but are not limited to, silicon nitride; and ceramic carbides include, but are not limited to, silicon carbide.

[0139] 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.

[0140] 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.

[0141] In some embodiments, the first thermal insulation layer 11, the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently meet the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K.

[0142] 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 .

[0143] In some embodiments, the outer insulation layer is a ceramic material layer.

[0144] 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.

[0145] 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.

[0146] Furthermore, the thickness of the first heat insulation layer 11 is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm; it can be optionally 1 mm to 8 mm.

[0147] 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; it can be optionally 1 mm to 8 mm.

[0148] In some embodiments, the thickness of the phase change material layer 131 accounts for 70% to 96% of the total thickness of the composite phase change layer 13, and can be optionally 86% to 96%. As an example, the thickness can be 70%, 75%, 80%, 82%, 85%, 86%, 90%, 92%, 95%, or 96%.

[0149] 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.

[0150] 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.

[0151] In some embodiments, the packaging layer 132 is an aluminum-plastic film or a polymer packaging film.

[0152] Furthermore, the packaging layer 132 includes a polypropylene layer, an aluminum layer, and a nylon layer stacked from the inside to the outside.

[0153] Furthermore, the polymer packaging film may be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0154] In some embodiments, the phase change material layer 131 includes a heat-insulating substrate in addition to the phase change material, and at least a portion of the phase change material is filled in the pores of the heat-insulating substrate. In other words, the pores of the heat-insulating substrate are filled with the phase change material.

[0155] The thermal insulation substrate may be a ceramic material substrate, such as ceramic fiber felt.

[0156] Furthermore, in some examples, at least a portion of the phase change material is directly filled in the pores of the thermal insulation substrate. In other examples, at least a portion of the phase change material can also be filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. It is understood that the same thermal insulation substrate can also include two states of phase change material: one in which the phase change material is directly filled in the pores of the thermal insulation substrate, and the other in which the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules.

[0157] It is understood that the phase change material layer 131 can be obtained by soaking a porous thermal insulation substrate such as ceramic fiber felt in a liquid phase change material, for example, by soaking it in a molten phase change material and then cooling it, or by soaking it in a phase change material solution and then drying or heat-insulating it. In addition to absorbing heat, the phase change material layer 131 also provides thermal insulation. When the phase change material vaporizes and breaks through the encapsulation layer 132, that is, the thermal insulation pad 10 fails, the thermal insulation substrate in the phase change material layer 131 can continue to provide thermal insulation. In other words, the phase change material directly fills the pores of the thermal insulation substrate.

[0158] In other embodiments, at least a portion of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. In other words, the pores of the thermal insulation substrate of the phase change material layer 131 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, wherein the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material. It is understood that in some examples, the pores of the thermal insulation substrate can also be directly filled with the phase change material and the aforementioned phase change microcapsules at the same time.

[0159] The above-mentioned phase change material layer 131 can be obtained by dispersing phase change microcapsules in a solvent to obtain a phase change microcapsule dispersion, then immersing a thermal insulation substrate in the phase change microcapsule dispersion to fill the phase change microcapsules in the pores of the thermal insulation substrate, and removing the solvent in the phase change microcapsule dispersion.

[0160] 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 insulation pad 10 vaporizes and breaks the packaging layer 132, that is, the insulation pad 10 fails. At this time, the insulation substrate in the phase change material layer 131 can continue to play an insulation role.

[0161] 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.

[0162] 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. As an example, the polymer matrix can be a phenolic resin matrix. It is understood that the polymer matrix is ​​not limited to this and can also be any one of polyacrylonitrile resin, melamine formaldehyde resin, and phenolic resin polymer.

[0163] Furthermore, the phase-change microcapsules have a Dv50 particle size of 5 to 8 μm. The Dv50 particle size, also known as the volume average particle size (Dv50), represents the particle size at which the cumulative volume distribution percentage of the particles reaches 50%, and can be measured using methods known in the art, for example, using a laser particle size analyzer (e.g., Malvern Master Size 3000).

[0164] 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.

[0165] 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.

[0166] The material selection of the above-mentioned thermal insulation substrate and ceramic particles in this application is the same as the selection range of the above-mentioned ceramic material layer. In some examples, the above-mentioned thermal insulation substrate is a ceramic fiber mat. The ceramic fiber mat has ceramic fibers as the core skeleton, which can not only be well infiltrated with liquid phase change materials, but also has low thermal conductivity, good high temperature resistance (1280°C), resistance to instantaneous thermal shock, flame retardancy and mechanical properties, no powdering, and is flexible and resilient, and is compatible with the battery pack manufacturing process.

[0167] In some examples, the thermal insulation substrate includes nano-ceramic fibers, which include at least one of silica fibers, alumina fibers, zirconia fibers, alumina-silicon ceramic fibers, borosilicate ceramic fibers, boron-alumina ceramic fibers, and zirconium-alumina-silicon ceramic fibers.

[0168] Furthermore, the average diameter of the nano-ceramic fibers is 200 nm to 800 nm, and the thickness of the thermal insulation substrate is 1 mm to 2 mm.

[0169] In some examples, the ceramic particles include, but are not limited to, at least one of boron nitride particles, silicon nitride particles, silicon carbide particles, and silicon dioxide particles. Furthermore, the ceramic particles have a Dv50 of 60 nm to 90 nm. By way of example, the Dv50 of the ceramic particles can be any value among 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 83 nm, 85 nm, and 90 nm, or between any two values. Silicon dioxide particles of this specific particle size facilitate doping and uniform dispersion in the substrate.

[0170] 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.

[0171] 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.

[0172] In some embodiments, the phase change material layer 131 in the composite phase change layer 13 includes a thermal insulation substrate and a phase change material, with at least a portion of the phase change material being filled in the thermal insulation substrate. This allows the composite phase change layer 13 to have good compressive properties. Furthermore, the strain of the composite phase change layer 13 when subjected to a stress of 0.5 MPa to 5 MPa is 8% to 20%, and further, the strain when subjected to a stress of 0.5 MPa to 4 MPa is 8% to 20%. Furthermore, the strain under the above stress is 10% to 20%, and further, 10% to 16%.

[0173] In some embodiments, the strain of the outer insulation layer is 25% to 70% when subjected to a stress of 0.5 MPa to 5 MPa, further 25% to 70% when subjected to a stress of 0.5 MPa to 3 MPa, and further 29% to 57% when subjected to a stress of 0.5 MPa to 2.8 MPa. The outer insulation layer has a certain degree of compressibility and can absorb battery expansion when the battery expands, thereby further improving the service life and thermal insulation performance of the insulation mat.

[0174] In some embodiments, the thermal insulation pad 10 includes a composite phase change layer 13, a first thermal insulation layer 11, and a second thermal insulation layer 12, wherein the composite phase change layer 13 is sandwiched between the first thermal insulation layer 11 and the second thermal insulation layer 12. Furthermore, the strain of the thermal insulation pad 10 when subjected to a stress of 0.5MPa to 4MPa is 15% to 35%, further, the strain when subjected to a stress of 0.5MPa to 3MPa is 15% to 35%, and further, 15% to 30%. In this way, the thermal insulation pad 10 has both good compression performance and thermal insulation performance, so that it has good thermal insulation performance when used in the thermal insulation structure of the battery, prevents the spread of thermal runaway, and can also absorb battery expansion, reducing the risks caused by battery expansion.

[0175] The stress-strain curves used in this article were obtained using the following method: A press was used to compress the sample at an inlet stress of 0.008 MPa at a rate of 2 mm / min until a certain pressure was reached. The tests were conducted at a temperature of 23°C ± 5°C, a relative humidity of 45% to 75%, and an atmospheric pressure of 86 kPa to 106 kPa.

[0176] 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.

[0177] Strain is the percentage change in thickness of a sample under stress relative to its initial thickness. The change in thickness under stress is measured by measuring the displacement relative to the initial position using a micrometer or pressure tester. The initial thickness of the sample is measured using a Mitutoyo 547-301 thickness gauge with an accuracy of ≤0.01mm. The test requires that both the insulation pad and the Mitutoyo 547-301 thickness gauge be parallel to the ground. Testing is performed at five locations, including the four corners and the center, with the average value of these five locations being used as the test value. Strain = displacement recorded by the micrometer or pressure tester / initial sample thickness.

[0178] 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.

[0179] Referring to FIG. 9 and FIG. 10 , another embodiment of the present application further provides a battery 30 , which includes any of the above-mentioned thermal insulation pads 10 .

[0180] Furthermore, the battery 30 further includes a plurality of battery cells 20, and the thermal insulation pad 10 is disposed between at least two adjacent battery cells 20. Optionally, a thermal insulation pad 10 is disposed between any two adjacent battery cells 20.

[0181] It is understandable that the above-mentioned thermal insulation pad 10 may also be provided between the battery cell 20 and the inner wall of the battery 30 shell.

[0182] In some embodiments, the above-mentioned battery 30 also includes a third adhesive layer, one side of which is arranged on the outer surface of the outer insulation layer (the first insulation layer 11 and / or the second insulation layer 12) of the insulation pad 10, and the other side is used to bond the insulation pad 10 to a designated position of the battery 30, for example, the other side is bonded to a surface (for example, a larger surface) of the battery cell 20.

[0183] The battery 30 is provided with the above-mentioned 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) thermal insulation pad 10, and the phase change material layer 131 in the 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.

[0184] The first and second stages are states before the failure of the thermal insulation pad 10, and the third and fourth stages are states after the failure of the thermal insulation pad 10. The third and fourth stages are not essential stages.

[0185] It is understood that the shape of the battery cell 20 includes but is not limited to square and cylindrical. The thermal insulation pad 10 can be arranged in a manner consistent with the shape of the battery cell 20.

[0186] In some embodiments, the battery cell 20 is square, and the 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.

[0187] Furthermore, the thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0188] 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.

[0189] 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.

[0190] For example, Figure 11 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.

[0191] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0192] 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.

[0193] Furthermore, the battery cell 20 and the shell 21 are rectangular shells, and the thermal 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.

[0194] As a further non-limiting example, the wall thickness of the housing is 0.5 mm to 0.8 mm.

[0195] Furthermore, the housing 21 is an aluminum alloy housing; for example, a third-series aluminum alloy housing or a fifth-series aluminum alloy housing.

[0196] 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%.

[0197] 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%.

[0198] 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.

[0199] Figure 12 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.

[0200] 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.

[0201] The following are specific examples.

[0202] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0203] Example 1

[0204] The thermal insulation pad 10 of Example 1, as shown in FIG2 , includes a first thermal insulation layer 11, a first adhesive layer 151, a composite phase change layer 13, a second adhesive layer 152, and a second thermal insulation layer 12, which are stacked in sequence. The first thermal insulation layer 11 is connected to the encapsulation layer 132 via the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 via the second adhesive layer 152. The composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132. The encapsulation layer 132 is disposed on the outer surface of the phase change material layer 131 and forms an encapsulation cavity. The phase change material layer 131 is disposed within the encapsulation cavity.

[0205] The first heat-insulating layer 11 is a silica aerogel ceramic felt with a thickness of 1 mm;

[0206] The thickness of the first adhesive layer 151 is 0.05 mm and the material is silicone adhesive layer;

[0207] In the composite phase-change layer 13, the phase-change material layer 131 comprises a thermal insulation substrate and a phase-change material filling the pores of the thermal insulation substrate. The specific composition of the phase-change material is shown in Table 1 below. The total mass content of the phase-change material in the phase-change material layer 131 is 60%. The thermal insulation substrate is a silica nano-ceramic fiber felt, and the encapsulation layer 132 is an aluminum-plastic film with a thickness of 0.1 mm. The total thickness of the composite phase-change layer 13 is 1 mm.

[0208] The thickness of the second adhesive layer 152 is 0.05 mm and the material is silicone adhesive layer;

[0209] The second heat insulation layer 12 is a silica aerogel ceramic felt with a thickness of 1 mm.

[0210] Example 2

[0211] The structure and materials of Example 2 are essentially the same as those of Example 1, differing only in that the total thickness of the composite phase change layer 13 is 2 mm. Specifically, the thickness of the encapsulation layer 132 remains unchanged, while the thickness of the thermal insulation substrate is increased, resulting in a total thickness of the composite phase change layer 13 of 2 mm. All other parameters remain unchanged.

[0212] Examples 3 to 8

[0213] It is basically the same as Example 1, except that the composition and / or ratio of the phase change material are different, as shown in Table 1.

[0214] Table 1

[0215] (1) The thermal insulation performance of the thermal insulation pads prepared in each embodiment was tested.

[0216] The test method is as follows: Heat the heating table to 600°C and maintain this temperature. Install temperature sensors on two opposite sides of the thermal insulation pad (a rectangle with a size of 100mm×100mm), place the thermal insulation pad on the heating table, and press the thermal insulation pad with an aluminum plate at a pressure of 3000N. By measuring the temperature of the two sides of the thermal insulation pad within 1200s, the thermal insulation effect of the thermal insulation pad can be determined. Among them, the side of the thermal insulation pad that is in direct contact with the heating table is the hot side, and the other side opposite to the hot side is the cold side. There are 3 temperature sampling points on each side, one is the center point, and the other two are symmetrically distributed with respect to the center point, with a spacing of 15mm between them.

[0217] The test results of Example 1 and Example 2 are shown in Figures 13 and 14, respectively. There are three curves corresponding to the three sampling points on the hot side and the cold side, as shown in the figure, where curves 1 to 3 are for the hot side and curves 4 to 6 are for the cold side.

[0218] Figure 13 shows that within the 1200-second test period, when the hot side temperature reached nearly 600°C, the cold side temperature remained below 150°C due to the insulating effect of the thermal pad. Specifically, within the first 300 seconds, while the hot side temperature rose, the cold side maintained a lower temperature plateau (approximately 50°C). As the test time increased and heat dissipated further, the cold side temperature began to rise and then remained essentially at a plateau around 100°C. This plateau temperature is shown in Table 1.

[0219] Figure 14 shows that within the 1200-second test period, when the hot side temperature reaches nearly 600°C, the cold side temperature ideally remains below 140°C due to the insulating effect of the thermal pad. Specifically, within the first 600 seconds, although the hot side temperature rises, the cold side maintains a lower temperature plateau (approximately 50°C). As the test progresses and heat diffusion further diffuses, the cold side temperature rises and then remains essentially at a plateau around 100°C, representing the phase transition temperature.

[0220] As can be seen from Table 1, by adjusting the components and proportions of the phase change material, the phase change temperature of the phase change material layer can be adjusted to meet the requirements of different battery cells.

[0221] (2) Calculations of phase change heat absorption were performed on 0.05 kg of the thermal insulation mat produced in Example 2. Comparisons were made using the same weight of water. The results showed that the thermal insulation mat's heat absorption capacity was approximately 83% of that of the same mass of water. This means that 30% of the heat transferred to adjacent battery cells was absorbed by the thermal insulation mat. The thermal insulation mat of this application has a heat absorption capacity roughly equivalent to that of water, which has a higher specific heat capacity. However, compared to using water as the phase change material, it is more battery-friendly.

[0222] Examples 9 to 16

[0223] This embodiment is essentially the same as Example 1, differing only in that the composite phase change layer 13 is different, specifically in that the phase change material therein is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. The composition of the phase change material is the same as that of Example 1, with the main difference being that the wall material of the phase change microcapsules includes a polymer matrix and ceramic particles filled in the polymer matrix. The mass ratio of the polymer matrix to the ceramic particles, the mass ratio of the polymer matrix to the core material, and the Dv50 particle size parameters of the phase change microcapsules are shown in Table 2 below. The polymer matrix is ​​a phenolic resin matrix, the ceramic particles are silica particles with a Dv50 of 0.5 μm, and the mass content of the phase change microcapsules in the phase change material layer is 60%.

[0224] The thermal insulation pads prepared in Examples 9 to 16 were subjected to a pressure resistance test, and the test method is as follows: a press is used to compress the thermal insulation pad at a compression rate of 2 mm / min. As the press is compressed, the greater the compression rate of the thermal insulation pad, the greater the stress on the thermal insulation pad. When the compression rate reaches a certain value, the packaging layer in the thermal insulation pad breaks, and the stress on the thermal insulation pad decreases rapidly. The inflection point where the stress decreases rapidly corresponds to the external pressure applied, which can reflect the pressure resistance of the thermal insulation pad. The test results are shown in Table 2.

[0225] Table 2

[0226] Example 17

[0227] It is basically the same as Example 1, with the only difference being that the composition of the phase change material layer in the composite phase change layer is different; specifically, the phase change material layer 131 includes a thermal insulation substrate and a phase change material filled in the pores of the thermal insulation substrate, and the thermal insulation substrate is also silica nano-ceramic fiber felt. The main difference is that the phase change material is replaced by an equal mass of silica sol.

[0228] The following is a compression performance test.

[0229] Stress-strain testing was conducted on the single composite phase-change layer sample from Example 1 (sample area: 100 mm x 100 mm). Compressive stress-strain curves were obtained, as shown in Figure 15. As can be seen, the average strain of the sample ranged from 8% to 20% when subjected to stresses of 0.5 MPa to 5 MPa, and further from 0.5 MPa to 4 MPa, and further from approximately 10% to 16%. The package failure rupture pressure of the thermally conductive layer was slightly greater than 4 MPa.

[0230] A stress-strain test was conducted on the first thermal insulation layer (silica aerogel ceramic felt) alone in Example 1 (sample area: 100 mm*100 mm), yielding a compressive stress-strain curve, as shown in Figure 16. It can be seen that the strain of the sample is 25% to 70% when subjected to a stress of 0.5 MPa to 5 MPa, 25% to 70% when subjected to a stress of 0.5 MPa to 3 MPa, and 29% to 57% when subjected to a stress of 0.5 MPa to 2.8 MPa.

[0231] The thermal insulation pad in Example 1 was used as a sample (sample area of ​​100mm*100mm), and multiple sets of parallel stress-strain tests were performed to obtain a compressive stress-strain curve, as shown in Figure 17. It can be seen that the strain of the thermal insulation pad as a whole is 15% to 35% when subjected to a stress of 0.5MPa to 4MPa, and further 15% to 35% when subjected to a stress of 0.5MPa to 3MPa, and further 15% to 30%.

[0232] 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.

[0233] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A thermal insulation pad, comprising: Thermal insulation pad body; and The strain detection component is arranged on the thermal insulation pad body.

2. The thermal insulation pad according to claim 1, wherein: The thermal insulation pad body includes an outer thermal insulation layer, and the strain detection component is located inside the outer thermal insulation layer or is arranged on the outer surface of the outer thermal insulation layer.

3. The thermal insulation pad according to claim 2, wherein: The strain detection component is arranged on the outer surface of the outer heat insulation layer. The heat insulation pad further includes a waterproof protective film, which is arranged on the outer surface of the strain detection component.

4. The thermal insulation pad according to any one of claims 2 to 3, wherein: The strain detection component has an external wire, and the external wire is led out from one side of the outer heat insulation layer.

5. The thermal insulation pad according to any one of claims 2 to 4, wherein: The thermal insulation pad meets at least one of the following conditions: (1) The ratio of the thickness of the strain detection member to the thickness of the outer heat insulation layer is 1:(10-500); (2) The thickness of the strain detection member is 10 μm to 50 μm; (3) The thickness of the outer insulation layer is 0.5 mm to 8 mm; (4) The outer thermal insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K; (5) The density of the outer insulation layer is 0.2 g / cm 3 ~0.22g / cm 3 ; (6) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating; (7) The outer heat insulation layer is a ceramic material layer; (8) The strain of the outer insulation layer when subjected to a stress of 0.5 MPa to 5 MPa is 25% to 70%; (9) The thermal insulation pad also includes a release adhesive layer, which includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

6. The thermal insulation pad according to any one of claims 2 to 5, wherein: The thermal insulation pad body also includes a composite phase change layer, which includes 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; the outer thermal insulation layer is arranged on at least one side of the composite phase change layer.

7. The thermal insulation pad according to claim 6, wherein: The strain detection component has a first surface away from the composite phase change layer, the outer heat insulation layer has a second surface away from the composite phase change layer, and a distance between the first surface and the second surface is ≥0.3 mm.

8. The thermal insulation pad according to claim 7, wherein: The distance between the first surface and the second surface is 0.3 mm to 0.5 mm.

9. The thermal insulation pad according to any one of claims 6 to 8, wherein: The thermal insulation pad meets at least one of the following conditions: (1) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm; (2) The thickness of the composite phase change layer is 1 mm to 6 mm; (3) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer; (4) The thickness ratio of the composite phase change layer to the outer thermal insulation layer is (0.15-12):1; (5) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film; (6) The thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the encapsulation layer are connected via the adhesive layer; (7) 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; (8) The length and width of the outer heat-insulating layer are respectively adapted to the length and width of the composite phase change layer; or at least one of the length and width of the outer heat-insulating layer is larger than the corresponding length or width of the composite phase change layer; (9) The strain of the composite phase change layer is 8% to 20% when subjected to a stress of 0.5 MPa to 5 MPa.

10. The thermal insulation pad according to any one of claims 6 to 9, 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.

11. The thermal insulation pad according to claim 10, 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.

12. The thermal insulation pad according to any one of claims 10 to 11, 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.

13. The thermal insulation pad according to any one of claims 10 to 12, wherein: The packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

14. The thermal insulation pad according to any one of claims 10 to 13, wherein: The 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.

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

16. The thermal insulation pad according to claim 15, 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.

17. The thermal insulation pad according to any one of claims 14 to 16, 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.

18. The thermal insulation pad according to any one of claims 10 to 17, wherein: The thermal insulation pad meets at least one of the following conditions: (1) The strain of the thermal insulation pad when subjected to a stress of 0.5 MPa to 4 MPa is 15% to 35%; (2) The 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.

19. The thermal insulation pad according to any one of claims 6 to 18, wherein: The phase change material layer includes a heat insulation substrate and a phase change material; Wherein, the phase change material is filled in the thermal insulation substrate.

20. The thermal insulation pad according to claim 19, wherein: The phase change material is filled in the pores of 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 wraps around the outer surface of the core material, and the core material includes the phase change material.

21. A battery, wherein: Comprising the thermal insulation pad according to any one of claims 1 to 20.

22. The battery according to claim 21, wherein The system further comprises a plurality of battery cells, wherein the thermal insulation pad is arranged between at least two adjacent battery cells.

23. The battery according to claim 22, wherein The thermal insulation pad is arranged between the large surfaces of two adjacent battery cells.

24. An electrical device, wherein: Comprising a battery as claimed in any one of claims 21 to 23.

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